PURPOSE: To eliminate from the use of a hot-water supplying apparatus the possibility of excessive opening or excessive narrowing of the control valve for the control of the flow rate of water so that the flow rate can be set in a stabilized state at an early point of time and hence the temperature of the hot water can be stabilized from an early stage.

CONSTITUTION: There are provided a heat exchanger 1; a burner 2 at which the degree of the combustion is variable; a feedwater thermistor 4 on the inlet side of the heat exchanger 1; a sensor 5 for determining the flow rate of water; a valve 6 for controlling the flow rate of water; a thermistor 3 for the hot water supplied provided on the outlet side of the heat exchanger 1; a temperature-setting part 7 by which to set a desirable temperature; a calculating part 10 for calculating the required calorific value from the feedwater temperature, set temperature, and flow rate of water; a first control part 11 for deciding correction values for individual temperatures of hot water; a second control part 12 for controlling a fuel supply part; and a third control part 13 for controlling the valve for controlling the flow rate of water.