To provide an opening device capable of locking with a chain of operations following the closing operation by means of a handle and preventing a locking failure.

The opening device comprises a frame body 2, a door body 4 and a lockable locking device 6. The locking device comprises a receiving seat 11 provided at the frame body; a latch bolt 12 provided at the door body so as to be insertable into and detachable from the receiving seat and energized to be inserted into the receiving seat; a first handle 13 and a second handle 14 provided at the door body and projected to one side and the other side of the door body respectively; a detaching means for detaching the latch bolt from the receiving seat based on the turning operation of the first handle; a connecting means 30 connecting the second handle in an integrally turnable manner to the first handle; and a latch bolt operation inhibiting means for inhibiting the operation of the latch bolt by the second handle with a chain of operations following the operation of the first handle for closing the door body.