<PAGE>
                                                                   EXHIBIT 31(b)
                                             ALLETE First Quarter 2007 Form 10-Q


      RULE 13a-14(a)/15d-14(a) CERTIFICATION BY THE CHIEF FINANCIAL OFFICER
            PURSUANT TO SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002


     I, Mark A. Schober, Senior  Vice President and Chief  Financial Officer  of
ALLETE, Inc. (ALLETE), certify that:

1.   I have reviewed this quarterly report on Form 10-Q for the quarterly period
     ended March 31, 2007, of ALLETE;

2.   Based on my knowledge, this report does not contain any untrue statement of
     a material  fact or omit to state a  material  fact  necessary  to make the
     statements made, in light of the circumstances  under which such statements
     were made,  not  misleading  with  respect  to the  period  covered by this
     report;

3.   Based on my  knowledge,  the  financial  statements,  and  other  financial
     information  included  in  this  report,  fairly  present  in all  material
     respects the financial  condition,  results of operations and cash flows of
     the registrant as of, and for, the periods presented in this report;

4.   The  registrant's  other  certifying  officer  and  I are  responsible  for
     establishing and maintaining disclosure controls and procedures (as defined
     in Exchange Act Rules  13a-15(e) and 15d-15(e))  and internal  control over
     financial  reporting  (as  defined  in  Exchange  Act Rules  13a-15(f)  and
     15d-15(f)) for the registrant and have:

     a.  Designed  such  disclosure  controls  and  procedures,  or caused  such
         disclosure   controls  and   procedures   to  be  designed   under  our
         supervision,  to  ensure  that  material  information  relating  to the
         registrant,  including its consolidated subsidiaries,  is made known to
         us by others within those entities,  particularly  during the period in
         which this report is being prepared;

     b.  Designed such internal control over financial reporting, or caused such
         internal  control over  financial  reporting  to be designed  under our
         supervision,  to provide reasonable assurance regarding the reliability
         of financial reporting and the preparation of financial  statements for
         external  purposes in accordance  with  generally  accepted  accounting
         principles;

     c.  Evaluated the effectiveness of the registrant's disclosure controls and
         procedures  and  presented  in this  report our  conclusions  about the
         effectiveness of the disclosure controls and procedures,  as of the end
         of the period covered by this report based on such evaluation; and

     d.  Disclosed  in this  report  any  change  in the  registrant's  internal
         control over financial  reporting that occurred during the registrant's
         most recent fiscal quarter (the  registrant's  fourth fiscal quarter in
         the case of an  annual  report)  that has  materially  affected,  or is
         reasonably  likely to  materially  affect,  the  registrant's  internal
         control over financial reporting; and

5.   The registrant's  other certifying  officer and I have disclosed,  based on
     our most recent evaluation of internal control over financial reporting, to
     the registrant's auditors and the audit committee of the registrant's board
     of directors (or persons performing the equivalent functions):

     a.  All significant  deficiencies and material  weaknesses in the design or
         operation  of  internal  control  over  financial  reporting  which are
         reasonably  likely to  adversely  affect  the  registrant's  ability to
         record, process, summarize and report financial information; and

     b.  Any fraud,  whether or not material,  that involves management or other
         employees  who have a  significant  role in the  registrant's  internal
         control over financial reporting.


Date:  May 4, 2007             Mark A. Schober
                               -------------------------------------------------
                               Mark A. Schober
                               Senior Vice President and Chief Financial Officer