Disclosed is a temperature control apparatus for a heater using an encoder switch and method thereof that controls an indoor temperature by driving a burner in accordance with a change of an indoor temperature and ventilating heated air indoors. The temperature control apparatus includes an encoder switch converting a user's set temperature value into a digital signal of a predetermined number of bits, a microcomputer for comparing the indoor temperature inputted in real time with the digital set temperature, driving the burner if the indoor temperature is lower than the set temperature by less than a predetermined temperature T.sub.1, and stopping the driving of the burner if the indoor temperature is high than the set temperature by more than a predetermined temperature T.sub.2, and a display unit for checking and displaying various kinds of error modes occurring while the burner is driven in accordance with a control signal inputted from the microcomputer.