A technique to reduce workload on an operator during mating of a lever connector is provided. A plug and a receptacle are pulled together by rotation of a lever in a locking direction. The lever has a pinion first driven surface facing in an unlocking direction. A receptacle housing has a rack first driving surface facing in a separating direction. In a state where the plug confronts the receptacle so as to mate the plug with the receptacle, a clearance between the pinion first driven surface and the rack first driving surface is smaller than a clearance between a contact piece and a pin portion. When the plug is moved toward the receptacle, the pinion first driven surface first comes into contact with the rack first driving surface and the lever rotates in the locking direction, and then the contact piece comes into contact with the pin portion.