A temperature control apparatus is provided. The temperature control apparatus includes an analog to digital (AD) converter digital-converting a measurement value transmitted from a plurality of temperature sensors; a control means comparing the measurement value transmitted from the AD converter with a preset desired value to perform PID calculation; and an output unit transmitting, to outside, a pulse width modulation (PWM) control signal transmitted form the control means, wherein an input-side isolator for isolation for each temperature sensor is provided between the AD converter and the temperature sensor, the input-side isolator is connected to each of the temperature sensors, and the control means sequentially operates the input-side isolators.