To provide a connector that can be simply positioned and easily and surely fitted even when the connectors cannot be seen.

Since introducing guides 9, 11 at a pair of corners adjacent to each other of four corner parts are formed higher than introducing guide projections 13, 15 at a pair of corners adjacent to each other, when a mating connector 3 is fitted and connected, the connector 3 is brought into contact with the higher introducing guide projections 9, 10, and fitted to a connector 1 along the introducing guide projections 9, 11, 13, 15. When the mating connector 3 is fitted an connected, the mating connector 3 is moved to bring into contact with the introducing guide projections 9, 11 installed at a pair of corners on the opposite side in the moving direction, for positioning, then the mating connector 3 is fitted and connected to the connector 1.