<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE
UNAUDITED CONSOLIDATED FINANCIAL STATEMENTS OF ADE CORPORATION FOR THE
SIX MONTHS ENDED OCTOBER 31, 1999 AND IS QUALIFIED IN ITS ENTIRETY BY
REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000

                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          APR-30-2000
<PERIOD-START>                             MAY-01-1999
<PERIOD-END>                               OCT-31-1999
<CASH>                                          39,476
<SECURITIES>                                         0
<RECEIVABLES>                                   11,521
<ALLOWANCES>                                         0
<INVENTORY>                                     26,855
<CURRENT-ASSETS>                                91,080
<PP&E>                                          29,755
<DEPRECIATION>                                       0
<TOTAL-ASSETS>                                 138,319
<CURRENT-LIABILITIES>                           17,740
<BONDS>                                         12,237
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           133
<OTHER-SE>                                     108,209
<TOTAL-LIABILITY-AND-EQUITY>                   138,319
<SALES>                                         25,987
<TOTAL-REVENUES>                                25,987
<CGS>                                           16,153
<TOTAL-COSTS>                                   16,153
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                               (522)
<INCOME-PRETAX>                               (12,292)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                           (12,292)
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                  (13,055)
<EPS-BASIC>                                     (0.98)
<EPS-DILUTED>                                   (0.98)