<PAGE>   1
                       SECURITIES AND EXCHANGE COMMISSION
                                        
                             Washington, D.C. 20549
                                        
                                   FORM 10-Q
                                        
                       Quarterly Report Under Section 13
                                or 15(d) of the
                        Securities Exchange Act of 1934
                                        
                         Commission File No. 001-12335
                                        
                      FOR THE QUARTER ENDED JUNE 30, 1998
                                        
                          BUTLER MANUFACTURING COMPANY
                                        
                       Incorporated in State of Delaware
                                        
                          BMA Tower - Penn Valley Park
                             Post Office Box 419917
                        Kansas City, Missouri 64141-0917
                                        
                             Phone: (816) 968-3000
               I.R.S. Employer Identification Number: 44-0188420
                                        
                     Shares of common stock outstanding at
                            JUNE 30, 1998: 7,665,761
                                        
The name, address and fiscal year of the Registrant have not changed since the
last report.
                                        
 The Registrant (1) has filed all reports required to be filed by Section 13 or
  15(d) of the Securities Exchange Act of 1934 during the preceding 12 months,
   and (2) has been subject to such filing requirements for the past 90 days.
<PAGE>   2
                                     INDEX

PART I. - FINANCIAL INFORMATION                                      Page Number


ITEM 1.   Financial Statements

    (1)   Consolidated Financial Statements (unaudited):

          Consolidated Statements of Operations for the Three and
          Six Month Periods Ended June 30, 1998 and 1997.                  3

          Consolidated Balance Sheets as of June 30, 1998 and
          December 31, 1997.                                               4

          Consolidated Statements of Cash Flows for the Six Month
          Periods Ended June 30, 1998 and 1997.                            5

    (2)   Notes to Consolidated Financial Statements                       6

ITEM 2.   Management's Discussion and Analysis of Financial Condition
          and Results of Operations                                        7-8

PART II. - OTHER INFORMATION

ITEM 5.   Other Matters                                                    9

ITEM 6.   Exhibits and Reports on Form 8-K                                 9

          In addition to historical information included herein, this report
          contains forward-looking statements and information that are based on
          management's beliefs as well as on assumptions made by and
          information currently available to management. These forward-looking
          statements and information are within the meaning of the Private
          Securities Litigation Reform Act of 1995. When used in this report,
          the words "anticipate," "intend," "plan," "believe," "estimate,"
          "project," and similar expressions are intended to identify
          forward-looking statements. Such statements are not guarantees of
          future performance and involve certain risks, uncertainties and
          assumptions which could cause the company's future results and
          stockholder values to differ materially from those expressed in such
          forward-looking statements.

          For additional comments, refer to the July 16, 1998 letter to
          shareholders, which is attached as exhibit 19.


                                     Page 2
  
<PAGE>   3
                BUTLER MANUFACTURING COMPANY AND SUBSIDIARIES

                    CONSOLIDATED STATEMENTS OF OPERATIONS

        For the three and six month periods ended June 30, 1998 and 1997

                                 (unaudited)
                  ($000's omitted except for per share data)
                                      

<TABLE>
<CAPTION>
                                                                    Three months ended                    Six months ended
                                                                         June 30,                              June 30, 
                                                             -------------------------------         -----------------------------
                                                                 1998                1997                1998               1997
                                                             -----------         -----------         -----------       -----------
<S>                                                          <C>                 <C>                <C>                <C>
Net Sales                                                    $   238,517         $   241,078         $   432,301       $   429,180
Cost of sales                                                    197,455             199,752             359,312           355,777
                                                             -----------         -----------         -----------       -----------
  Gross profit                                                    41,062              41,326              72,989            73,403
                                                                                                                         
Selling, general and administrative expenses                      31,326              30,226              59,604            57,653
                                                             -----------         -----------         -----------       -----------
   Operating income                                                9,736              11,100              13,385            15,750
                                                                                                                         
Other income, net                                                    181                 363                 651               229
Gain on sale of Grain Systems                                        ---              22,000                 ---            22,000
                                                             -----------         -----------         -----------       -----------
   Earnings before interest and taxes                              9,917              33,463              14,036            37,979
Interest expense                                                   1,483               1,631               2,868             2,910
                                                             -----------         -----------         -----------       -----------
   Pretax earnings                                                 8,434              31,832              11,168            35,069
                                                                                                                         
Income tax expense                                                 3,516              12,840               5,091            14,181
                                                             -----------         -----------         -----------       -----------
   Net earnings                                              $     4,918         $    18,992         $     6,077       $    20,888
                                                             ===========         ===========         ===========       ===========
           
Basic earnings per common share                              $      0.64         $      2.49         $      0.79       $      2.75
                                                             ===========         ===========         ===========       ===========
Diluted earnings per common share                            $      0.64         $      2.46         $      0.79       $      2.71
                                                             ===========         ===========         ===========       ===========
                                                                                     
Basic weighted average number of shares                        7,663,184           7,627,463           7,658,208         7,601,030
Diluted weighted average number of shares                      7,735,523           7,716,113           7,728,047         7,693,786


</TABLE>

 Net earnings from operations, which excludes the gain on the sale of the Grain
 Systems division, were $5,693 or $.74 per share, and $7,589 or $.99 per share,
  for the three months ended and six months ended June 30, 1997, respectively.



          See Accompanying Notes to Consolidated Financial Statements.


                                     Page 3
<PAGE>   4
                BUTLER MANUFACTURING COMPANY AND SUBSIDIARIES
                         CONSOLIDATED BALANCE SHEETS

                     June 30, 1998 and December 31, 1997

                                 (unaudited)
                               ($000's omitted)
                                      

<TABLE>
<CAPTION>
                                                                           1998           1997
                                                                        ----------    ----------
<S>                                                                    <C>            <C>
ASSETS
  Current assets:
    Cash and cash equivalents                                          $  25,309      $   5,515
    Receivables, net                                                     118,680        106,882
    Inventories:              
      Raw materials                                                       38,036         59,937
      Work in process                                                      9,273          7,859
      Finished goods                                                      50,648         21,317
      Lifo reserve                                                       (11,877)       (10,822)
                                                                       ---------      --------- 
        Total inventory                                                   86,080         78,291
                      
    Real estate developments in progress                                  17,997         22,401
    Deferred tax assets                                                    7,811          7,812
    Other current assets                                                  11,982         12,422
                                                                       ---------      --------- 
      Total current assets                                               267,859        233,323
                          
  Investments and other assets                                            38,921         35,887
  Assets held for sale                                                     9,423          9,423
  Property, plant and equipment, at cost                                 245,422        239,747
    Less accumulated depreciation                                       (147,770)      (143,408)
                                                                       ---------      --------- 
       Net property, plant and equipment                                  97,652         96,339
                                                                       ---------      --------- 
                                                                       $ 413,855      $ 374,972
                                                                       =========      =========
LIABILITIES AND SHAREHOLDERS' EQUITY
  Current liabilities:
    Notes payable                                                      $   1,114      $  21,280
    Current maturities of long-term debt                                   5,763          5,862
    Accounts payable                                                      94,239         72,266
    Dividends payable                                                      1,073          1,069
    Accrued liabilities                                                   53,718         55,846
    Taxes on income                                                        9,205          8,181
                                                                       ---------      --------- 
      Total current liabilities                                          165,112        164,504

  Deferred tax liabilities                                                 3,561          3,561
  Other noncurrent liabilities                                            15,460         16,423
  Long-term debt, less current maturities                                 68,301         33,918

  Shareholders' equity: 
    Common stock, no par value, authorized        
     20,000,000 shares, issued 9,088,200 shares,     
     at stated value                                                      12,623         12,623
    Cumulative foreign currency translation adjustment                      (434)            26
    Retained earnings                                                    180,066        175,373
                                                                       ---------      --------- 
                                                                         192,255        188,022 
  Less cost of common stock in treasury, 1,422,439
   shares in 1998 and 1,451,205 shares in 1997                            30,834         31,456
                                                                       ---------      --------- 
    Total shareholders' equity                                           161,421        156,566
                                                                       ---------      --------- 
                                                                       $ 413,855      $ 374,972
                                                                       =========      =========
</TABLE>


         See Accompanying Notes to Consolidated Financial Statements.


                                    Page 4
<PAGE>   5
                BUTLER MANUFACTURING COMPANY AND SUBSIDIARIES
                    CONSOLIDATED STATEMENTS OF CASH FLOWS

           For the six month periods ended June 30, 1998 and 1997

                                 (unaudited)
                              ($000's omitted)


<TABLE>
<CAPTION>
                                      
                                                                 1998           1997
                                                              ----------     ----------
<S>                                                           <C>            <C>
Cash flows from operating activities:
  Net earnings                                                $    6,077     $   20,888
  Adjustments to reconcile net earnings to net
  cash used in operating activities:              
    Depreciation and amortization                                  7,346          5,965
    Gain on sale of Grain Systems                                    --         (13,299)
    Equity earnings on joint ventures                               (156)           (87)
  Change in asset and liabilities, net of businesses
  acquired and sold:                             
    Receivables                                                  (11,798)       (16,092)
    Inventories                                                   (7,789)       (18,721)
    Real estate developments in progress                           4,404          6,438
    Other current assets                                             441         (5,093)
    Current liabilities excluding short-term debt                 20,869          1,572
                                                              ----------     ----------
       Net cash provided (used) in operating activities           19,394        (18,429)

Cash flows from investing activities:
  Capital expenditures                                            (7,744)       (13,191)
  Sale of Grain Systems                                              --          33,748
  Acquisition of new businesses                                      --          (7,697)
  Other, net                                                      (3,793)          (191)
                                                              ----------     ----------
       Net cash provided (used) by investing activities          (11,537)        12,669

Cash flows from financing activities;
  Payment of dividends                                            (2,141)        (1,817)
  Proceeds from issuance of long-term debt                        35,000            -- 
  Repayment of long-term debt                                       (620)          (442)
  Net change in short-term debt                                  (20,265)         4,238
  Sale and issuance of treasury stock                                622            561
  Purchase of treasury stock                                         --             --
  Other, net                                                        (199)         1,804
                                                              ----------     ----------
       Net cash provided by financing activities                  12,397          4,344

Effect of exchange rate changes on cash                             (460)          (582)
                                                              ----------     ----------
  Net increase (decrease) in cash and cash equivalents            19,794         (1,998)
Cash and cash equivalents at beginning of year                     5,515          2,013
                                                              ----------     ----------

Cash and cash equivalents at June 30                          $   25,309     $       15
                                                              ==========     ==========


</TABLE>


SUPPLEMENTAL SCHEDULE OF NONCASH INVESTING AND FINANCING ACTIVITIES:
The company purchased all of the capital stock of Modu-Line, Inc. on June 11,
1997 for 191,777 shares of the company's common stock issued from the treasury,
plus deferred cash payments and closing costs totaling $.5 million. The company
also retired Modu-Line's existing bank debt of $4.5 million. In conjunction with
the acquisition, the value of treasury stock issued is shown below.

     Fair value of assets acquired                         $11,982
     Cash paid                                               4,982
                                                           -------
     Treasury stock issued for purchase of capital stock   $ 7,000
                                                          ========



          See Accompanying Notes to Consolidated Financial Statements.
                                        
                                        
                                     Page 5
<PAGE>   6
                 BUTLER MANUFACTURING COMPANY AND SUBSIDIARIES
                   NOTES TO CONSOLIDATED FINANCIAL STATEMENTS


NOTE 1 - BASIS OF PRESENTATION
The accompanying unaudited consolidated condensed financial statements have been
prepared in accordance with the accompanying policies described in the
consolidated financial statements and related notes included in Butler
Manufacturing Company's 1997 Form 10-K. It is suggested that those consolidated
statements be read in conjunction with this report. The year-end financial
statements presented were derived from the company's audited financial
statements. In the opinion of management, the accompanying consolidated
financial statements reflect all adjustments necessary for a fair presentation
of the financial position of Butler Manufacturing Company and the results of its
operations.

NOTE 2 - NEW ACCOUNTING PRONOUNCEMENT 
Derivative Instruments and Hedging Activities 
In June, 1998 the Financial Accounting Standards Board issued Statement No. 133,
"Accounting for Derivative Instruments and Hedging Activities."  This new
statement replaces existing pronouncements and practices with an integrated
accounting and reporting standard for derivatives and hedging activities. It
requires that every derivative instrument be recorded in the balance sheet as
either an asset or liability at its fair value, and changes in a derivative's
fair value be recognized in current earnings or other comprehensive income. The
company is required to adopt Statement No. 133 starting January 1, 2000. The
company does not expect adoption of this standard to have a material impact on
the company's financial statements.

Comprehensive Income 
In June, 1997 the Financial Accounting Standards Board issued FASB Statement No.
130, "Reporting of Comprehensive Income" which requires reporting and display of
comprehensive income and its components in a full set of financial statements.
The company has adopted this statement as of January 1, 1998 as required.
"Foreign Currency Translation Adjustment Total" is the company's only
comprehensive income item as defined by the statement. Comprehensive income,
including after tax adjustments for foreign currency translation losses, was
$4.8 million and $18.8 million, for the quarters ending June 30, 1998 and 1997,
respectively, and $5.8 million and $20.6 million for the six month periods
ending June 30, 1998 and June 30, 1997, respectively.

NOTE 3 - ACQUISITION AND DISPOSITION OF BUSINESS 
On June 11, 1997 the company announced the acquisition of Modu-Line Windows,
Inc. for 191,777 shares of Butler stock having a market value of approximately
$7 million, plus deferred cash payments and closing costs totaling $.5 million.
The company also retired Modu-Line's existing bank debt of approximately $4.5
million. The fair value of assets acquired of $12 million consists primarily of
receivables, inventory, and equipment valued at $6.2 million with the remaining
amount allocated to goodwill which will be amortized over 40 years.

On June 23, 1997 the company sold the business and substantially all of the
assets and liabilities used in the business of the Grain Systems division, an
unincorporated division of the company, to CTB, Inc., a privately owned company
in Indiana. The business was sold for approximately $34 million in cash. The
sale of the Grain Systems division generated an after-tax gain of $13.3 million,
or $1.72 per share. Net cash proceeds to the company were approximately $23
million.



                                     Page 6
<PAGE>   7
    ITEM 2. MANAGEMENT'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND
                             RESULTS OF OPERATIONS


LIQUIDITY AND CAPITAL RESOURCES

Cash and cash equivalents increased $19.8 million in the first six months of
1998, primarily due to the $35 million private placement of senior notes secured
at the end of the first quarter and used to pay down the company's short-term
line of credit and fund working capital requirements. For the six months ended
June 30, 1998 domestic short term borrowings averaged $20 million for 118 days
compared to $29 million for 181 days in 1997.

In June, 1998 the company amended its existing bank credit agreement to extend
its expiration date to June, 2001 and to reduce the credit available to $40
million from $50 million. As of June 30, 1998 $1.8 million of the domestic
credit line was utilized to provide a bank letter of credit to secure insurance
obligations. The company also maintains a separate line of credit of
approximately $2.5 million for its United Kingdom subsidiary. Management
believes the company's operating cash flow, along with bank credit lines, is
sufficient to meet future liquidity requirements. 

Capital expenditures were $7.7 million for the first six months of 1998 compared
to $13.1 million a year ago. Total capital expenditures are projected to be
approximately $18 million in 1998 compared to actual expenditures of $30 million
in 1997. Capital expenditures were greater a year ago due to costs incurred to
increase capacity in the domestic and international metal buildings businesses,
as well as the Architectural Products segment.

On June 16, 1998 the Board of Directors declared a regular dividend of $.14 per
share of company common stock payable on July 10, 1998 to shareholders of
record on June 26, 1998.

RESULTS OF OPERATIONS 
   
Net sales of $239 million for the quarter ended June 30, 1998 were comparable to
the same quarter a year ago. Increased revenue in the company's Architectural
Products segment and the domestic buildings business offset the loss of revenue
from the Grain Systems division which was sold in June, 1997. For the six months
ended June 30, 1998 net sales were $432 million compared with $429 million in
1997 including $19 million of sales from the Grain Systems division.

The second quarter 1998 consolidated gross profit of $41.1 million was also
comparable to the $41.3 million recorded a year ago. For the six months ended
June 30, 1998 consolidated gross profit was $73 million compared to $73.4
million in 1997. Gross profit increases in the Building Systems, Construction
Services and Architectural Products segments, approximated the loss of gross
profit dollars due to the sale of the Grain Systems division.

The Building Systems segment's earnings increased on modestly higher sales due
to a 16% increase in the domestic metal buildings division's earnings during the
first six months of the year.  Good results from the domestic metal buildings
business more than offset losses incurred by the company's Brazilian building
systems business which incurred significant operating losses during the period
due to operational difficulties.

Net earnings from operations for the quarter ended June 30, 1998 were $4.9
million or $.64 per common share compared to $19 million or $2.46 per common
share in 1997, including $13.3 million, or $1.72 per common share, from the
sale of our Grain Systems division. The net earnings from operations for the
six months ended June 30, 1998 were $6.1 million or $.79 per common share
compared to net operating income of $7.6 million or $.99 per common share last
year, including $1.7 million of earnings from the Grain Systems business.

Total backlog of $341 million on June 30, 1998 was up 13% from a year ago.
Product backlog was 17% higher, and construction services backlog was 6% lower.

                                     Page 7
<PAGE>   8
YEAR 2000 UPDATE
Many computer systems used by companies, governments and individuals around the
world use only the last two digits to refer to a year. Therefore, these
computer programs may not properly recognize a year that begins with "20"
instead of the familiar "19". If not corrected, many computer applications
could fail or create erroneous results. This has come to be known as the "Year
2000 problem."

The company believes it has identified, or has processes in place to identify,
and will be able to address all of its critical Information Technology, Other
Technology, and Business Issues ("Business") Year 2000 problems in a timely
manner. Costs incurred and expected to be incurred in remediation of the
company's Year 2000 problems have not been, nor are they expected to be
material.

In 1997, the company reviewed its principal business, manufacturing, and
engineering computer systems and applications to determine the impact of the
Year 2000 problem on these systems, and to establish a plan to address critical
issues ("Compliance Plan"). In 1998, the company engaged a consultant to assess
the company's Compliance Plan and its progress toward effecting the Plan in a
timely manner. The consultant looked at three areas: Information Technology
("IT"), such as the company's business, manufacturing and engineering systems;
Other Technology ("Non-IT") such as telecommunications and manufacturing
equipment which contained embedded micro-controllers; and Business Issues
related to service providers, vendors and customers. The consultant advised the
company that nothing was identified that in and of itself would indicate that
the company would not be successful with its Year 2000 compliance efforts.

The company's Compliance Plan identifies important IT and Non-IT risk areas and
assigns a priority to each. It also calls for the company to determine whether
its significant service suppliers, vendors and customers are Year 2000 compliant
and if there would be a material effect on the company's business, results of
operations, or financial condition if these parties do not timely become Year
2000 Compliant. It also requires for the company to consider its potential
liability to third parties if it is not Year 2000 compliant. These
determinations and assessments are underway. Finally, the Compliance Plan
requires the company to identify its most reasonably likely worst case Year 2000
problem scenarios and to develop a contingency plan to handle them. These
scenarios have yet to be identified or contingency plans, if needed, created.

RECENT ACCOUNTING STANDARD
In June, 1998 the Financial Accounting Standards Board issued Statement No. 133,
Accounting for Derivative Instruments and Hedging Activities with adoption
required starting in January 1, 2000. The statement replaces existing
pronouncements and requires that every derivative instrument be recorded in the
balance sheet as either an asset or liability at its fair value, and changes in
a derivative's fair value be recognized in current earnings or other
comprehensive income. The company does not expect adoption of this standard to
be material.

MANAGEMENT AND BOARD OF DIRECTORS TRANSITION
In June, 1998 the beginning of a transition within the senior management group
of the company was announced with the election of John J. Holland as Executive
Vice President of the company. He was previously Vice President - Finance of
the company, and will be named Chief Executive Officer in 1999, succeeding
Robert H. West, the current Chairman and Chief Executive Officer, who announced
his decision to retire from the company and its Board of Directors in mid-1999.

It was also announced that Larry C. Miller has been elected Vice President -
Finance, succeeding John J. Holland as Chief Financial Officer.

Also, in June it was announced that Robert E. Cook resigned as a member of the
Board of Directors of the company due to expanded international management
responsibilities at his company. He had been a member of the company's Board of
Directors since 1987. Commensurate with his resignation the Board of Directors
reduced the number of Directors from ten to nine.


                                     Page 8
<PAGE>   9

PART II. - OTHER INFORMATION

Item 5.   Other Matters

          Stockholders who intend to present proposals for inclusion in the
          company's proxy statement for the next annual meeting of stockholders
          on April 20, 1999 must forward them to the company at BMA Tower (P.O.
          Box 419917), Penn Valley Park, Kansas City, Missouri 64141-0917,
          ATTENTION: Secretary, so that they are received not later than
          February 11, 1999. In addition, proxies appointed by the Board may
          confer discretionary authority to vote on matters which are not
          included in the proxy statement but which are raised at the annual
          meetings by stockholders, unless the company is provided notice of the
          matter on or before January 22, 1999.

Item 6.   Exhibits and Reports on Form 8-K.

     (a)  Exhibits

          (19) July 16, 1998 letter to shareholders

          (27) Financial Data Schedule

     (b)  Reports on Form 8-K

          The company has not filed any reports on Form 8-K during the quarter
          ended June 30, 1998.



                                     Page 9

<PAGE>   10

                                   SIGNATURES


Pursuant to the requirement of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned thereunto duly authorized.


BUTLER MANUFACTURING COMPANY


August 11, 1998                             /s/ Larry C. Miller
-----------------------                     ----------------------------------
Date                                        Larry C. Miller
                                            Vice President - Finance Treasurer
                                            and Chief Financial Officer


August 11, 1998                             /s/ Richard O. Ballentine
-----------------------                     ----------------------------------
Date                                        Richard O. Ballentine
                                            Vice President, General Counsel
                                            and Secretary




                                    Page 10
 
<PAGE>   11

                                                                      EXHIBIT 99



                                 EXHIBIT INDEX

Exhibit
Number        Description
-------       ------------------------------------------

19            July 16, 1998 Letter to Shareholders

27            Financial Data Schedule