PURPOSE: To obtain a holding device which is able to surely hold a printed board even if it is vertical or horizontal in position by a method wherein slits are provided to an L-shaped holder extending to its bent part, and the L-shaped holder is fixed to a mounting table taking advantage of machine screws inserted into slits.

CONSTITUTION: A holding device is composed of a holder 5 L-shaped in cross section, which is fixed to a printed board 1 with machine screws 2 and provided with two slits 5a and 5b that extend vertical to its lengthwise direction reaching to its bent part, mounting protrusions 6c and 6d which are formed by bending protrusions provided to the upper side of a chassis and provided with tapped holes 6a and 6b, and two machine screws 7 which are inserted into the slits. When the printed board 1 is mounted at a horizontal position, it is kept horizontal in position, the machine screws 7 are fitted into the tapped holes 6a and 6b and fastened. When the printed board 1 is kept at a vertical position, the machine screws 7 are unfastened, and the board 1 is fitted upright and then fixed by fastening the machine screws again.