A storage device including a bearing member, a storage unit, and a casing is provided. The casing has a bottom plate, a top plate and a main assembling structure. The bearing member has an interfering portion and a sub-assembling structure. The storage unit has a body with a first surface and a second surface opposite to each other, a limiting portion and a terminal set. Parts of the terminal set and the limiting portion are located at the first surface. The storage unit and the interfering portion are accommodated in the casing. The interfering portion provides interfering force to the limiting portion, and the bottom plate provides a supporting force to the second surface, so that the storage unit is positioned in the casing. The main assembling structure and the sub-assembling are assembled detachably to each other to configure or detach the bearing member and the casing.