A quick connector includes a socket including a threaded portion detachably fastenable to a water tap, an opposing free end portion and three inside flanges equiangularly spaced between the threaded portion and the free end portion, and a connection member including a connector body defining an axial through hole in communication with the socket and a fitting defining three insertion grooves for the insertion of the respective inside flanges and three sliding grooves respectively connected to the insertion grooves corresponding to the three inside flanges and disposed adjacent to the position-limit surface for allowing sliding therein of the respective inside flanges. Thus, the user can use to the quick connector to rapidly and detachably connect an oral irrigator to a water tap in a convenient and hygienic manner, avoiding the problem that oral irrigator cannot effectively clean tartar due to insufficient water pressure caused by a leakage of water.