To provide a lock having a safety function allowing unlocking by a simple operation even in a locked condition.

This lock 1 is provided with a latch 6 interlocking with rotation of a hub 3 to protrude/retract to/from a lock main body 2, a lock member 7 restricting rotation of the hub 3, and an unlocking member 75 interlocking with a connection member 5, which interlocks with the hub 3, and the latch 6. The unlocking member 75 is provided with a sharp point part 76 engaged with a claw type part 71 arranged in a lock hub 61 of the lock member 7. When the latch 6 is retracted into the lock main body 2, the unlocking member 75 is pushed by an unlocking energizing part 19 to be turned. According to this, the lock hub 61 is turned, and a lock slider 60 is moved upward. When the lock slider 60 is moved, the lock member 7 is set in an unlocked condition.