Abstract: An electrically operable cylinder lock device includes a body with a bore housing a rotatable barrel, having a key slot. The barrel is locked in position normally by a spring-loaded bar which extends axially of the barrel and is movable radially thereof. A slot in the barrel receives the bar and cam formations in the slot act to lift the bar to a withdrawn position in which it can be held by an electromagnet. A plunger in the bore has a slotted end to receive the tip of the key and provides a driving connection between the key and an output cam.