PURPOSE: To make certain attachment or detachment of a printed board to or from a gage possible by providing mechanism in which the printed board is mounted due to revolving force and drawn out with a screw.

CONSTITUTION: A printed board 2 is mounted on or drawn out of the guide case 3 of a gage 1 via a high-density connector. The printed board 2 when attached and detached is moved via an attaching-detaching device. The attaching-detaching device comprises an attaching-detaching handle 11 fixed to a fitting 4 via a revolution supporting pin 10, a draw-out handle supporting pi 9 and a draw-out handle supporting bed 8 moved via a screwy jack 21 and an attaching-detaching pin 7 engaged with an attaching-detaching pin hole 18 in the printed board. The attaching-detaching device is revolved and engaged with the printed board 2, which is moved by the screwy jack 21 in a linear direction so as to be connected electrically and certainly without giving unnecessary power.