PURPOSE: To enable a contact defect between a Dumet and a semiconductor device to be surely detected by measuring a voltage between two terminals while sandwiching a leadless type glass sealed electronic part at its side surfaces by a pair of elastic members in a conditions wherein the side surface are pressed by elastic members.

CONSTITUTION: A leadless type glass sealed diode 1 is provided with Dumets 4 as terminal portions having circular flange terminals 2 on bases and distal ends opposing to each other while sandwiching a semiconductor device 3 therebetween with a prescribed contact pressure and a cylindrical glass 5 for sealing the circumferential surfaces of the Dumets 4 in the manner that the terminals 2 are exposed outside. Rounded portions 5a formed on the edges of the glass 5 by a heat treatment for bringing the glass 5 into close contact with the circumferential surfaces of the Dumets 4 generate gaps between the glass 5 and the inner side surfaces of the terminals 2. The diode 1 is positioned in a prescribed inspection position and elastic members 7 made of rubber are pressed against the side surface of the diode 1 by a pressing machine 6. By measuring a voltage under this condition by a measuring probe 9 connected to a voltage measuring instrument 8, a contact defect can be detected.