1. An accommodation device comprising:a casing body for accommodating a protective component;
a casing cover fixed to the casing body so as to form an accommodation space for accommodating the protective component, an air breathing hole being formed in the casing cover for communicating the accommodation space to an outside of the accommodation device;
a filter accommodation portion formed on a part of an outside surface of the casing cover and having a bottom surface formed on the part of the outside surface of the casing cover, wherein an outside end of the air breathing hole is opened at the bottom surface while an inside end of the air breathing hole is opened at an inside surface of the casing cover;
a filter element fixed to the bottom surface of the filter accommodation portion for covering the outside end of the air breathing hole;
a filter cover located at the outside surface of the casing cover and fixed to the casing cover for covering the filter element;
a cover positioning portion formed in the filter accommodation portion of the casing cover for positioning the filter cover with respect to the filter accommodation portion; and
a peripheral wall portion formed on the outside surface of the casing cover for surrounding the filter accommodation portion,
wherein a height of the peripheral wall portion from the bottom surface of the filter accommodation portion is larger than a height of the filter cover from the bottom surface.