Provided is a method of controlling temperature of warm water of a bidet. The method includes: a first step of detecting a current temperature of warm water stored in a storage tank; a second step ofgradually adjusting intensity of power supplied to a heating means depending on a difference when the current temperature of the warm water is lower than a target temperature; and a third step of cutting the power supplied to the heating means when the current temperature of the warm water is equal to the target temperature after the second step. Therefore, the warm water can be precisely maintained at a set temperature by checking a temperature of cleaning water in a storage tank using a sensor in real time, and gradually controlling intensity of power supplied to a heating means on the basisof the checked water temperature.