PURPOSE: To eliminate a person's help required in the course of observation, and to improve the work efficiency by using a connecting jig utilizing the suction force of a vacuum pump, for connecting the lead of electronic parts with the probe of a measuring instrument.

CONSTITUTION: This connecting jig is constituted of a contact type spring built-in probe 1, a bushing 3, a frame 4, a hose fitting part 5, etc. In such state, first of all, the tip of the probe 1 is allowed to contact with the lead 12 of electronic parts 11 being an object to be observed. Subsequently, by opening a vacuum pump control valve 7, and leading the suction force of a vacuum pump 7 into a cylindrical frame 4 through a hose 6, a bushing 3 is adsorbed onto a electronic circuit loading substrate 10, and the lead 12 and the probe 20 of a measuring instrument can be connected. In such way, the connecting jig fulfills the duty of relay for connecting the lead 12 and the probe 20 of the measuring instrument, by utilizing the suction force of the vacuum pump 8, and it becomes unnecessary to ask for a person's help at the time of probing required in the course of observation, and the work efficiency can be improved.