The present disclosure relates to a water pump in which a channel is formed so that a fluid introduced through an inlet side passes through a bearing part and a channel inside the rotor accommodation part and the rotor is formed so that the fluid may circulate, so a lubricating action of a bearing rotatably coupled to the rotor is smoothed and a pressure difference between upper and lower sides of an assembly of the rotor and an impeller assembly is reduced, thereby reducing abnormal noise and vibration in the bearing part.