A cover opening-closing device comprises a rod, a casing in which at least a portion of the rod is stored, a lock unit, an interlock mechanism, and a connection unit. The lock unit can rotate about a central axis line between a lock position, in which locking with the cover is possible, and a release position, in which locking is not possible. The interlock mechanism is configured so that the rotation of the lock unit and the displacement of the rod are interlocked. The connection unit is configured so as to connect the lock unit to the casing and to restrict displacement of the lock unit in the direction of the central axis line.