PURPOSE: To take measures against leakage radio waves or the like by a simplified manufacturing process by a method wherein a mechanism chassis on a fixation plate is fixed by a claw installed on an enclosure and the fixation plate is set in continuity to a grounding pattern on a printed-circuit board by a plate spring.

CONSTITUTION: A mechanism chassis 1 in which a disk driving gear is housed is attached, via legs 3 provided with vibrationproof damper rubbers 3a, onto a fixation plate 2 which is fixed to an enclosure 6. The fixation plate 2 is fitted and fixed to a plurality of claws 7 formed so as to be fitted to the sidewall 6a of the enclosure 6. In addition, plate springs 5 and elastic sheets 8 are installed between the bottom part of the fixation plate and the enclosure 6 so as to be fitted respectively to recessed parts 6c, 6b. The chassis 2 is fixed to enclosure 6, and its trembling is prevented. In addition, since the plate springs 5 are fitted and fixed to the sidewall 6a of the enclosure 6 which is formed integrally with a plate spring 9, a soldering operation is not required. In addition, a grounding pattern on a printed-circuit board 4 is connected electrically to the fixation plate at a grounding potential via the plate springs 5, 9, and leakage radio waves are prevented.