In a flat-conductor connector having an automatic lock mechanism for a flat conductor, a fitting connection operation of a flat conductor is enabled to be reliably performed again after the flat conductor is extracted. A flat-conductor connector 1 includes a lock member including a slip-off stop locking surface configured to pass through a flat conductor housed in a housing chamber of a housing in the thickness direction of the flat conductor and lock the flat conductor. The lock member includes a supporting portion configured to support the slip-off stop locking surface so as to be displaceable between a locking position at which the lock member is locked with and stops the flat conductor from slipping off and a lock cancellation position at which the lock member is unlocked from the flat conductor to cause the flat conductor to be extractable from the housing chamber.