Embodiments of the invention provide a moisture absorbing mechanism for condensing excessive moisture in an environment primarily thereon so that the condensed moisture is absorbed by an absorbent material. In one embodiment, the moisture absorbing mechanism includes a dew condensation trapping mechanism (moisture collector) provided on a surface of an absorbent material such as silica gel or activated carbon in such a fashion that the absorbent material is covered with the dew condensation trapping mechanism. The moisture collector has a structure obtained by stacking a plurality of mesh sheets; a structure formed from a porous material having good air permeability, such as a sponge; a structure obtained by aligning fibers in the form of a brush; or the like. Three-dimensional narrow spaces are formed in each of the moisture collectors, and excessive moisture in the environment is condensed primarily inside each of the narrow spaces because a vapor pressure inside the narrow space is relatively low. The moisture absorbing mechanism is attached to a base inside a magnetic disk drive or the like with an adhesive.