Disclosed herein is an AC line signal detection device including: a semiconductor integrated circuit; and a conversion section adapted to rectify an AC line signal and convert the rectified signal to an input signal to be fed to the semiconductor integrated circuit, wherein the semiconductor integrated circuit includes a monitoring section adapted to divide the AC line signal into a plurality of voltage ranges with at least one reference voltage proportional to the amplitude of the AC line signal to monitor within which voltage range the AC line signal falls; a measuring section adapted to measure a duration for which the AC line signal remains in each of the voltage ranges; and a determination section adapted to determine, based on the monitoring result of the monitoring section and the measurement result of the measuring section, whether the duration for which the AC line signal remains in each of the voltage ranges exceeds a set time which can be set in advance to make a pass/fail determination on the AC line signal.