It is aimed to prevent connectors in a connected state from being easily separated. A connector (A) includes a male housing (10) including a receptacle (12), a female housing (30) to be connected to the male housing (10) by being inserted into the receptacle (12), and a retainer (36) (movable locking member, locking means) and a lock receiving portion (19) (locking means) provided on the male housing (10) and the female housing (30) and configured to lock the male housing (10) and the female housing (30) in a connected state by being locked inside the receptacle (12). The locking of the retainer (36) and the lock receiving portion (19) is released by an unlocking tool (40) inserted into the receptacle (12).