Abstract: In an IC tester comprising a tester part and a handler which includes two test stations or an IC tester comprising a tester part and two handlers, useless waiting times wasted by the tester part are eliminated. Means (SO) is provided for inputting a simultaneous measurement mode into the handler 2, and when the simultaneous measurement mode is inputted, the handler waits, in case the test preparation in the first test station 15a is completed and the test preparation in the second test station 15b is not completed, till the test preparation in the second station is completed, and when the test preparation in the second station is completed, the handler transmits the test preparation complete signals of both the stations to the tester part 1.

Abstract: An IC testing method is disclosed in which IC's to be tested are placed on IC carriers disposed in an m-row, n-column array on a test tray in a loader, and the IC's to be tested are connected to sockets disposed as an m-row, k-column array on a socket attachment in a manner corresponding to every a-th column of the IC carriers in a testing section for purpose of measurement. n and k are integers equal to or greater than two, n=ak where a is an integer equal to or greater than two.