A voltage detection circuit detects an input voltage in first and second periods to average by using a switch circuit and a sampling circuit. At this time, the input voltage of the second period is added to the input voltage of the first period so that a polarity of variations is opposite, the variations being in relative errors of a plurality of resistors for dividing the input voltage, in input offset voltages of a voltage amplifier for amplifying an inputted minute voltage, and in input offset voltages of a comparator for comparing an amplified voltage value with a certain level.