The present invention provides a nozzle assembly for a bidet, the nozzle assembly comprising: a nozzle unit which moves along a curved line and comprises a water supply hose connected to a water supply source; and a driving unit having a winding member for rotating/driving such that the length of extension of the nozzle unit is adjusted, the driving unit guaranteeing that the nozzle unit moves along a curved line, where the length of extension of the nozzle unit is adjusted in multiple steps, and the withdrawing rotation angle, by which the winding member rotates in order to change the length of extension of the nozzle unit from one of the steps to the adjacent upper step, is different in each step. The length of extension of the nozzle unit can be adjusted such that the interval of water ejection positions is constant.