A self check-type flame detector includes a casing provided with a monitoring window formed therein. A wavelength generation unit is disposed inside the casing and generates a wavelength in a direction of the monitoring window. A wavelength detection element is disposed inside the casing and detects the wavelength. A comparison unit is provided with a wavelength DB for storing intensity of a reference wavelength and determines whether the monitoring window has been contaminated. A display unit is located outside the casing and displays a state of the monitoring window. A communication unit is disposed inside the casing and configured to receive operation information for the wavelength generation unit, to provide the operation information to the wavelength generation unit, and to transmit the intensity of the wavelength, or a normal signal or a contamination signal of the monitoring window.