Abstract: Disclosed herein is a hot/cold water supply system with an improved control part. Cold water that has remained in a pipe is re-circulated through a circulating water pipe and is re-supplied into and heated by a boiler rather than being discharged out of a faucet, and the temperature of the water is adjusted in a thermo-and-geared valve to a temperature preset by a user so that water with a low temperature deviation can be supplied to the user. Further, an excessive load is prevented from being applied to the thermo-and-geared valve. Water of different temperatures preset by users can be supplied to corresponding control zones. A sudden deviation in temperature can be prevented when the boiler re-ignites. When the temperature of water reaches a preset temperature, a control panel indicates it to the user on a display and/or by providing a sound, thus making it more convenient to use.