A control method of an infrared detector, for obtaining a wider dynamic range and preventing an over-range, is disclosed. The method includes: monitoring a value acquired in response to an electric current flowing in each of a plurality of infrared detection elements configuring the infrared detector, and lowering, when the value acquired in response to the electric current flowing in the infrared detection element reaches a threshold value within a detection time, sensitivity of the infrared detection element within the detection time.