PURPOSE: To facilitate mounting of an electronic unit by turning a knob by providing clamping means rotating in the surface vertical to a direction of pressing a terminal on the unit, and providing engaging means on a member, to which the pressing force of the terminal of a body is applied.

CONSTITUTION: An engaging member 20 is inserted to hold from both side surfaces of the member with projections 14-G for positioning guide of a detachable LSI module 14, and inserted until the lower surface of a connector 15 exposed from the lower portion of the unit makes contact with the prescribed wiring pattern 17-1 of the printed board 17 of an electronic device body. A knob 13 is rotated in a direction of an arrow A until the projections 13-1, 13-2 of the knob 13 are engaged with the engaging part 20-1 of a holding member 20. The upper surface of the projection 13-1 and the lower surface of the engaging part 20-1 are inclined in the same direction to each other. Accordingly, a conductive connector 15 is pressed by strong pressure to the printed wirings 17-1 with a small rotary force of the knob by rotating the knob 13 clockwise.