To reduce the number of part items for constituting locking/ unlocking members, by serially incorporating the electric locking/ unlocking member and the manual locking/unlocking member, so as to interlock with each other, for effectively utilizing an inside space of a lock case.

In this locking/unlocking mechanism of an electric lock, the electric locking/unlocking member is composed of a driving piece having one end part journaled to an operation lever of a solenoid horizontally arranged in the lock case, and having a central part journaled to one fixing shaft; and while, the manual locking/ unlocking member is composed of a thumb turn top joint, an operation piece engaging with the thumb turn top joint, and a locking piece journaled to the other fixing one shaft together with the operation piece, so as to cooperate with this operation piece, and having an engaging part for mutually nonseparably engaging with the other end part of the driving piece.