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                                                                   EXHIBIT 10.17

                          REVOLVING LINE OF CREDIT NOTE

$1,500,000.00                                              Palo Alto, California
                                                                 October 15,2004

      FOR VALUE RECEIVED, the undersigned MICRUS CORPORATION ("Borrower")
promises to pay to the order of WELLS FARGO BANK, NATIONAL ASSOCIATION ("Bank")
at its office at Peninsula RCBO, 400 Hamilton Avenue, Palo Alto, California, or
at such other place as the holder hereof may designate, in lawful money of the
United States of America and in immediately available funds, the principal sum
of One Million Five Hundred Thousand Dollars ($1,500,000.00), or so much thereof
as may be advanced and be outstanding, with interest thereon, to be computed on
each advance from the date of its disbursement as set forth herein.

DEFINITIONS:

      As used herein, the following terms shall have the meanings set forth
after each, and any other term defined in this Note shall have the meaning set
forth at the place defined:

      (a) "Business Day" means any day except a Saturday, Sunday or any other
day on which commercial banks in California are authorized or required by law to
close.

      (b) "Fixed Rate Term" means a period commencing on a Business Day and
continuing for 1,2,or 3 months, as designated by Borrower, during which all or a
portion of the outstanding principal balance of this Note bears interest
determined in relation to LIBOR; provided however, that no Fixed Rate Term may
be selected for a principal amount less than One Hundred Thousand Dollars
($100,000.00); and provided further, that no Fixed Rate Term shall extend beyond
the scheduled maturity date hereof. If any Fixed Rate Term would end on a day
which is not a Business Day, then such Fixed Rate Term shall be extended to the
next succeeding Business Day.

      (c) "LIBOR" means the rate per annum (rounded upward, if necessary, to the
nearest whole 1/8 of 1%) and determined pursuant to the following formula:

                  LIBOR =         Base LIBOR
                         -------------------------------
                         100% - LIBOR Reserve Percentage

      (i) "Base LIBOR" means the rate per annum for United States dollar
deposits quoted by Bank as the Inter-Bank Market Offered Rate, with the
understanding that such rate is quoted by Bank for the purpose of calculating
effective rates of interest for loans making reference thereto, on the first day
of a Fixed Rate Term for delivery of funds on said date for a period of time
approximately equal to the number of days in such Fixed Rate Term and in an
amount approximately equal to the principal amount to which such Fixed Rate Term
applies. Borrower understands and agrees that Bank may base its quotation of the
Inter-Bank Market Offered Rate upon such offers or other market indicators of
the Inter-Bank Market as Bank in its discretion deems appropriate including, but
not limited to, the rate offered for U.S. dollar deposits on the London
Inter-Bank Market.

      (ii) "LIBOR Reserve Percentage" means the reserve percentage prescribed by
the Board of Governors of the Federal Reserve System (or any successor) for
"Eurocurrency

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Liabilities" (as defined in Regulation D of the Federal Reserve Board, as
amended), adjusted by Bank for expected changes in such reserve percentage
during the applicable Fixed Rate Term.

      (d) "Prime Rate" means at any time the rate of interest most recently
announced within Bank at its principal office as its Prime Rate, with the
understanding that the Prime Rate is one of Bank's base rates and serves as the
basis upon which effective rates of interest are calculated for those loans
making reference thereto, and is evidenced by the recording thereof after its
announcement in such internal publication or publications as Bank may designate.

INTEREST:

      (a) Interest. The outstanding principal balance of this Note shall bear
interest (computed on the basis of a 360-day year, actual days elapsed) either
(i) at a fluctuating rate equal to the Prime Rate in effect from time to time,
or (ii) at a fixed rate per annum determined by Bank to be two and three
quarters percent (2.75%) above LIBOR in effect on the first day of the
applicable Fixed Rate Term. When interest is determined in relation to the Prime
Rate, each change in the rate of interest hereunder shall become effective on
the date each Prime Rate change is announced within Bank. With respect to each
LIBOR selection hereunder, Bank is hereby authorized to note the date, principal
amount, interest rate and Fixed Rate Term applicable thereto and any payments
made thereon on Bank's books and records (either manually or by electronic
entry) and/or on any schedule attached to this Note, which notations shall be
prima facie evidence of the accuracy of the information noted.

      (b) Selection of Interest Rate Options. At any time any portion of this
Note bears interest determined in relation to LIBOR, it may be continued by
Borrower at the end of the Fixed Rate Term applicable thereto so that all or a
portion thereof bears interest determined in relation to the Prime Rate or to
LIBOR for a new Fixed Rate Term designated by Borrower. At any time any portion
of this Note bears interest determined in relation to the Prime Rate, Borrower
may convert all or a portion thereof so that it bears interest determined in
relation to LIBOR for a Fixed Rate Term designated by Borrower. At such time as
Borrower requests an advance hereunder or wishes to select a LIBOR option for
all or a portion of the outstanding principal balance hereof, and at the end of
each Fixed Rate Term, Borrower shall give Bank notice specifying: (i) the
interest rate option selected by Borrower; (ii) the principal amount subject
thereto; and (iii) for each LIBOR selection, the length of the applicable Fixed
Rate Term. Any such notice may be given by telephone (or such other electronic
method as Bank may permit) so long as, with respect to each LIBOR selection, (A)
if requested by Bank, Borrower provides to Bank written confirmation thereof not
later than three (3) Business Days after such notice is given, and (B) such
notice is given to Bank prior to 10:00 a.m. on the first day of the Fixed Rate
Term, or at a later time during any Business Day if Bank, at it's sole option
but without obligation to do so, accepts Borrower's notice and quotes a fixed
rate to Borrower. If Borrower does not immediately accept a fixed rate when
quoted by Bank, the quoted rate shall expire and any subsequent LIBOR request
from Borrower shall be subject to a redetermination by Bank of the applicable
fixed rate. If no specific designation of interest is made at the time any
advance is requested hereunder or at the end of any Fixed Rate Term, Borrower
shall be deemed to have made a Prime Rate interest selection for such advance or
the principal amount to which such Fixed Rate Term applied.

      (c) Taxes and Regulatory Costs. Borrower shall pay to Bank immediately
upon demand, in addition to any other amounts due or to become due hereunder,
any and all (i) withholdings, interest equalization taxes, stamp taxes or other
taxes (except income and


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franchise taxes) imposed by any domestic or foreign governmental authority and
related in any manner to LIBOR, and (ii) future, supplemental, emergency or
other changes in the LIBOR Reserve Percentage, assessment rates imposed by the
Federal Deposit Insurance Corporation, or similar requirements or costs imposed
by any domestic or foreign governmental authority or resulting from compliance
by Bank with any request or directive (whether or not having the force of law)
from any central bank or other governmental authority and related in any manner
to LIBOR to the extent they are not included in the calculation of LIBOR. In
determining which of the foregoing are attributable to any LIBOR option
available to Borrower hereunder, any reasonable allocation made by Bank among
its operations shall be conclusive and binding upon Borrower.

      (d) Payment of Interest. Interest accrued on this Note shall be payable on
the last day of each month, commencing October 30,2004.

      (e) Default Interest. From and after the maturity date of this Note, or
such earlier date as all principal owing hereunder becomes due and payable by
acceleration or otherwise, the outstanding principal balance of this Note shall
bear interest until paid in full at an increased rate per annum (computed on the
basis of a 360-day year, actual days elapsed) equal to four percent (4%) above
the rate of interest from time to time applicable to this Note.

BORROWING AND REPAYMENT:

      (a) Borrowing and Repayment. Borrower may from time to time during the
term of this Note borrow, partially or wholly repay its outstanding borrowings,
and reborrow, subject to all of the limitations, terms and conditions of this
Note and of any document executed in connection with or governing this Note;
provided however, that the total outstanding borrowings under this Note shall
not at any time exceed the principal amount stated above. The unpaid principal
balance of this obligation at any time shall be the total amounts advanced
hereunder by the holder hereof less the amount of principal payments made hereon
by or for any Borrower, which balance may be endorsed hereon from time to time
by the holder. The outstanding principal balance of this Note shall be due and
payable in full on September 30, 2005.

      (b) Advances. Advances hereunder, to the total amount of the principal sum
stated above, may be made by the holder at the oral or written request of (i)
Michel Mounler, Robert Stem, Tom Holdych or Jim Robbins, any two acting
together, who are authorized to request advances and direct the disposition of
any advances until written notice of the revocation of such authority is
received by the holder at the office designated above, or (ii) any person, with
respect to advances deposited to the credit of any deposit account of any
Borrower, which advances, when so deposited, shall be conclusively presumed to
have been made to or for the benefit of each Borrower regardless of the fact
that persons other than those authorized to request advances may have authority
to draw against such account. The holder shall have no obligation to determine
whether any person requesting an advance is or has been authorized by any
Borrower.

      (c) Application of Payments. Each payment made on this Note shall be
credited first, to any interest then due and second, to the outstanding
principal balance hereof. All payments credited to principal shall be applied
first, to the outstanding principal balance of this Note which bears interest
determined in relation to the Prime Rate, if any, and second, to the

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outstanding principal balance of this Note which bears interest determined in
relation to LIBOR, with such payments applied to the oldest Fixed Rate Term
first.

PREPAYMENT:

      (a) Prime Rate- Borrower may prepay principal on any portion of this Note
which bears interest determined in relation to the Prime Rate at any time, in
any amount and without penalty.

      (b) LIBOR. Borrower may prepay principal on any portion of this Note which
bears interest determined in relation to LIBOR at any time and in the minimum
amount of One Hundred Thousand Dollars ($100,000.00); provided however, that if
the outstanding principal balance of such portion of this Note is less than said
amount, the minimum prepayment amount shall be the entire outstanding principal
balance thereof. In consideration of Bank providing this prepayment option to
Borrower, or if any such portion of this Note shall become due and payable at
any time prior to the last day of the Fixed Rate Term applicable thereto by
acceleration or otherwise, Borrower shall pay to Bank immediately upon demand a
fee which is the sum of the discounted monthly differences for each month from
the month of prepayment through the month in which such Fixed Rate Term matures,
calculated as follows for each such month:

      (i)   Determine the amount of interest which would have accrued each month
            on the amount prepaid at the interest rate applicable to such amount
            had it remained outstanding until the last day of the Fixed Rate
            Term applicable thereto.

      (ii)  Subtract from the amount determined in (i) above the amount of
            interest which would have accrued for the same month on the amount
            prepaid for the remaining term of such Fixed Rate Term at LIBOR in
            effect on the date of prepayment for new loans made for such term
            and in a principal amount equal to the amount prepaid.

      (iii) If the result obtained in (ii) for any month is greater than zero,
            discount that difference by LIBOR used in (ii) above.

Each Borrower acknowledges that prepayment of such amount may result in Bank
incurring additional costs, expenses and/or liabilities, and that it is
difficult to ascertain the full extent of such costs, expenses and/or
liabilities. Each Borrower, therefore, agrees to pay the above-described
prepayment fee and agrees that said amount represents a reasonable estimate of
the prepayment costs, expenses and/or liabilities of Bank. If Borrower falls to
pay any prepayment fee when due, the amount of such prepayment fee shall
thereafter bear interest until paid at a rate per annum two percent 2%) above
the Prime Rate in effect from time to time (computed on the basis of a 360-day
year, actual days elapsed). Each change in the rate of interest on any such past
due prepayment fee shall become effective on the date each Prime Rate change is
announced within Bank.

EVENTS OF DEFAULT:

      This Note is made pursuant to and is subject to the terms and conditions
of that certain Credit Agreement between Borrower and Bank dated as of October
15,2004, as amended from

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time to time (the "Credit Agreement"). Any defined event of default under the
Credit Agreement shall constitute an "Event of Default" under this Note.

MISCELLANEOUS:

      (a) Remedies. Upon the occurrence of any Event of Default, the holder of
this Note, at the holder's option, may declare all sums of principal and
interest outstanding hereunder to be immediately due and payable without
presentments, demand, notice of nonperformance, notice of protest, protest or
notice of dishonor, all of which are expressly waived by each Borrower, and the
obligation, if any, of the holder to extend arty further credit hereunder shall
immediately cease and terminate. Each Borrower shall pay to the holder
immediately upon demand the full amount of all payments, advances, charges,
costs and expenses, including reasonable attorneys' fees (to include outside
counsel fees and an allocated costs of the holder's in-house counsel), expended
or incurred by the holder in connection with the enforcement of the holder's
rights and/or the collection of any amounts which become due to the holder under
this Note, and the prosecution or defense of any action in any way related to
this Note, including without limitation, any action for declaratory relief,
whether incurred at the trial or appellate level, in an arbitration proceeding
or otherwise, and including any of the foregoing incurred in connection with any
bankruptcy proceeding (inducting without limitation, any adversary proceeding,
contested matter or motion brought by Bank or any other person) relating to any
Borrower or any other person or entity.

      (b) Obligations Joint and Several. Should more than one person or entity
sign this Note as a Borrower, the obligations of each such Borrower shall be
Joint and several.

      (c) Governing Law. This Note shall be governed by and construed in
accordance with the laws of the State of California.

      IN WITNESS WHEREOF, the undersigned has executed this Note as of the date
first written above,

MICRUS CORPORATION

By: /s/ Robert A. Stern
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Title: Chief Financial Officer

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