An electrical device may be provided with: a housing to which a battery pack is attached detachably by sliding the battery pack in a sliding direction; a battery connection terminal configured to be electrically connected to the battery pack attached to the housing; and a terminal cover configured to move between a protection position for protecting the battery connection terminal and an exposure position for exposing the battery connection terminal. The housing may include a cover rail extending along the sliding direction. The terminal cover may include: a cover body having a shape that at least partially covers the battery connection terminal; and a hook formed integrally with the cover body, and the hook is engaged with the cover rail so as to slide in the sliding direction.