The connector comprises a housing having a connection hole where a pipe with a flange is inserted, a retainer having a latching portion that retains the pipe by being arranged at a location facing the connection hole and engaged with the flange, and a checker that is supported by the housing at the retaining position and is movable from the retaining position to the connection confirmation position when the pipe is inserted into the connection hole up to the normal connection position. The checker is configured to release the engagement between the latching portion and the flange, when at the connection confirmation position, by having the retainer that is engaged with the flange of the pipe at the normal connection position pushed to expand the distance of the retainer so that the pipe can be pulled out from the connection hole.