A magnetic disk drive is provided which can attain the reduction in size and thickness without deteriorating the sealing performance for a space defined by a base and a cover. In one embodiment, a cover member is fixed to a base member with fixing screws. An FPC assembly is formed with leg portions extending from respective appropriate positions toward the cover member. The edges of the leg portions are abutted against the cover member fixed to the base member. Further, a stress member is provided between the base member and the FPC assembly. When the cover member is fixed to the base member to urge the FPC assembly adjacent the stress member, the stress member collapses to induce stress from the stress member, whereby a frictional force is generated at abutment surfaces of the cover member and the leg portions, thus fixing the FPC assembly.