An optical module which can be inserted into and removed from a cage, the optical module includes a lock pin inserted into a lock hole provided in the cage and engaging the cage and the optical module with each other in a state where the optical module is inserted into the cage; a tongue having an axial part and configured to be rotated with respect to the axial part in a direction where the insertion of the lock pin into the lock hole is released; and a bail configured to be rotated with respect to a rotational axel so that the tongue is rotated. The engagement of the cage and the optical module formed by insertion of the lock pin into the lock hole is released by rotating the bail 90 degrees.