In a connector fitting construction of the invention, a slider 60 is slidably supported within a housing 53 of a female connector 50 housing, and when the female connector is to be fitted relative to a male connector 70, the slider cooperates with compression springs 59 to flex a lock arm 56 so as to retainingly engage the lock arm with the male connector 70. A pair of abutment projections 64 are formed respectively at opposite side portions of a lower surface of a slider arm 62 provided at the slider 60. A pair of stopper projections 72 are formed on an upper surface of a housing 71 of the male connector 70, and are pressed respectively against the abutment projections 64 during a connector fitting operation to move the slider 60 toward a rear end of the female connector 50. An abutment surface 72a of a generally trapezoidal shape is formed on a front surface of each of the stopper projections 72. An abutment surface 64a of the abutment projection 64 is a slanted surface which is slanting downwardly rearwardly, and the abutment surface 72a of the stopper projection 72 is a slanted surface which is slanting downwardly forwardly.