A connector includes a connector housing configured to receive terminal fixtures inside of the connector housing. The connector includes a locking member including an arm having an end supported by an outer peripheral wall, and configured to lock with a mating connector in an engagement state due to flexible deformation of the arm. The connector includes a front holder inserted in the connector housing from an engagement side of the connector housing for preventing the terminal fixtures from falling off. The connector includes a flex-prevention locking mechanism between the outer peripheral wall and the front holder for preventing the outer peripheral wall from flexing.