A lever is rotatably mounted on an inner housing of a female connector and assists a fitting operation through engagement of an engagement portion of a locking arm of the female connector with an engagement projection of a male connector and a fitting canceling operation in association with rotation thereof. An opening in the lever allows the tip of a finger of an operator to be brought into contact with an operation access portion of the locking arm so as to press the operation access portion, and a lever locking canceling finger catch portion of the lever is located in a position and formed into a shape which allow the finger of the operator to be hooked thereon such that the tip of the finger is in contact with the operation access portion of the locking arm.