PURPOSE: To prevent erroneous insertion by measuring the impedance of semicon ductor parts and comparing it with reference data before semiconductor parts are inserted.

CONSTITUTION: When semiconductor parts 2 sent from a parts supply part reach the terminal part of a transporting shoot 5 and is stopped, contact pins 7 arranged in parallel are moved forward and are brought into contact with corresponding lead terminals 2A from both sides of parts 2 to measure the impedance between lead terminals 2A, and this detected data is sent to a detecting part 11. The detecting part 11 extracts reference data of prescribed semiconductor parts 15 and collates and compares reference data 12 and detected data 10 with each other. If the collation results in coincidence, the detecting part 11 sends the Yes signal to a control part 13 to drive a hand head, and parts 2 are inserted to a printed board. It is discriminated automatically whether the insertion of parts 2 is permitted or not before parts 2 are inserted to the printed board, thereby preventing erroneous insertion to improve the reliability.