It is aimed to provide a connector capable of ensuring the integrity of a lock arm and a detector in the process of deflecting the lock arm and enhancing a degree of freedom in designing the lock arm. A detector (60) movable in a front-back direction between a standby position and a detection position is assembled with a housing (10). The detector (60) includes a contact portion (78) displaceable together with a front end part (27) of a lock arm (23) during the interference of the front end part (27) of the lock arm (23) and a mating lock (44) contacting the front part (27) of the lock arm (23) in a height direction intersecting with the front-back direction at the standby position. The contact portion (78) stands up in the height direction from a front end part of the locking arm and then projects forward.