A motor drive device includes a case including a first surface and a housing portion that opens to the first surface side, a terminal block including a terminal to which an electric wire extending to an outside of the case is connectable and being housed in the housing portion, an openable and closable cover covering the opening, and a lock unit restricting opening and closing of the cover and bringing the cover into a locked state in a state where the cover is closed. The lock unit is provided on the cover to be rotatable about an axis perpendicular to the first surface in a state where the cover is closed. An unlocked state in which the cover is openable and the locked state are switched according to rotation angle of the lock unit. The lock unit includes a state indicator indicating that the cover is in the locked state.