In semiconductor devices according to related art, it is impossible to sufficiently evaluate column ADC interference. According to one embodiment, a semiconductor device includes a plurality of analog/digital conversion circuits that are arranged in a column direction of a pixel array and convert a pixel output signal output from the pixel array for each row into a digital value, and a conversion signal selection circuit that selects one of the pixel output signal and a test signal having a test voltage for each analog/digital conversion circuit according to a test pattern and outputs the selected signal.