A plug type connector, and more particularly a plug type connector having a locking function when the plug type connector is connected to a counter connector, coupling the plug type connector to the counter connector. A locking member is formed by a slender by a slender locking piece configured from a synthetic resin molded product, the operation load which is required for flexurally deforming the locking piece can be increasingly or decreasingly adjusted. The plug type connector comprises contact portions, the locking piece, a press operating member, and a backup member. The backup member has the function of adjusting the level of the operation load of the locking piece. In another embodiment, even when the locking member is made of metal, the enclosure of the counter connector is not shaved by a prying force applied on the counter connector, and hence the stability of the locked state can be enhanced. A locking member of the plug type connector is produced by bending a metal wire rod having a circular section shape.