To improve operationability by installing a longitudinal handle and a releasing member interlocked with the handle to an inner seat and an outer seat mounted on the indoor and outdoor surfaces of a door.

When the central section of an internal handle 6 is pushed, the handle 6 is pushed against the energizing force of coil springs 13, 14, and a releasing member 8 is rotated in the clockwise direction. When the central section of an external handle 7 is pulled, the handle 7 is drawn against the energizing force of a helical spring 17, and a releasing member 9 is turned in the clockwise direction. When the upper section or lower section of the handle 6 is pushed, the member 8 is revolved in the clockwise direction. When the upper section or lower section of the handle 7 is pulled, the member 9 is rotated in the clockwise direction. Since each operating end 82, 92 of the members 8, 9 is engaged with the operating member of a latch lock 10, a locking piece is released from a latch head through the operating member, and the lock 10 is released and a door is brought to the state, in which the door can be opened. Accordingly, the door can be opened smoothly and surely, and the structure can be simplified.