A connector has a first housing (10) with two detection terminals (13) and a second housing (20) with a resilient deforming portion (25). A detection unit (40) is in the second housing (20) and has two connecting portions (42) that rub against the detection terminals (13) in the process of connecting the two housings (10, 20). The connecting portions (42) are connected to the detection terminals (13) when the housings (10, 20) are connected properly. Fixed contact portions (45) and movable contact portions (50) release a shorted state of the connecting portions (42) as the resilient deforming portion (25) is deformed and short the connecting portions (42) as the resilient deforming portion (25) is resiliently restored. A catch preventing structure (51) prevents foreign matter from being caught at the detection contact portions (45, 50) when the housings (10, 20) are separated.