A pipe coupling member comprising: a cylindrical coupling body having a fluid passage and an annular spring fitting groove formed on an inner peripheral surface of the fluid passage; a valve element disposed in the fluid passage, the valve element being displaceable in a direction of a longitudinal axis of the fluid passage between a closed position where the valve element closes the fluid passage and an open position where the valve element opens the fluid passage; and a coil spring formed by helically winding a wire, the coil spring being disposed between the coupling body and the valve element to urge the valve element toward the closed position; the coil spring having: a fitting portion having an outer diameter larger than an inner diameter of the fluid passage, the fitting portion being fitted and secured in the spring fitting groove; a valve support portion supporting the valve element; and an expanding-contracting portion configured to expand and contract in the direction of the longitudinal axis when the valve element is displaced between the closed position and the open position; the coil spring being characterized by: a locking portion contiguous with the fitting portion and having an outer diameter larger than an inner diameter of the fitting portion when fitted in the spring fitting groove, the locking portion formed by winding the wire a plurality of turns such that the turns of wire are adjacent to each other in the direction of the longitudinal axis; and the expanding-contracting portion extending between the locking portion and the valve support portion. a cylindrical coupling body having a fluid passage and an annular spring fitting groove formed on an inner peripheral surface of the fluid passage; a valve element disposed in the fluid passage, the valve element being displaceable in a direction of a longitudinal axis of the fluid passage between a closed position where the valve element closes the fluid passage and an open position where the valve element opens the fluid passage; and a coil spring formed by helically winding a wire, the coil spring being disposed between the coupling body and the valve element to urge the valve element toward the closed position; the coil spring having: a fitting portion having an outer diameter larger than an inner diameter of the fluid passage, the fitting portion being fitted and secured in the spring fitting groove; a valve support portion supporting the valve element; and an expanding-contracting portion configured to expand and contract in the direction of the longitudinal axis when the valve element is displaced between the closed position and the open position; the coil spring being characterized by: a locking portion contiguous with the fitting portion and having an outer diameter larger than an inner diameter of the fitting portion when fitted in the spring fitting groove, the locking portion formed by winding the wire a plurality of turns such that the turns of wire are adjacent to each other in the direction of the longitudinal axis; and the expanding-contracting portion extending between the locking portion and the valve support portion. a fitting portion having an outer diameter larger than an inner diameter of the fluid passage, the fitting portion being fitted and secured in the spring fitting groove; a valve support portion supporting the valve element; and an expanding-contracting portion configured to expand and contract in the direction of the longitudinal axis when the valve element is displaced between the closed position and the open position; the coil spring being characterized by: a locking portion contiguous with the fitting portion and having an outer diameter larger than an inner diameter of the fitting portion when fitted in the spring fitting groove, the locking portion formed by winding the wire a plurality of turns such that the turns of wire are adjacent to each other in the direction of the longitudinal axis; and the expanding-contracting portion extending between the locking portion and the valve support portion. a locking portion contiguous with the fitting portion and having an outer diameter larger than an inner diameter of the fitting portion when fitted in the spring fitting groove, the locking portion formed by winding the wire a plurality of turns such that the turns of wire are adjacent to each other in the direction of the longitudinal axis; and the expanding-contracting portion extending between the locking portion and the valve support portion.