An image pickup device may include an image pickup unit in which a plurality of pixels are arranged, the plurality of pixels outputting a first and second pixel signals, and an analog-to-digital (AD) conversion circuit that outputs a digital difference signal. The AD conversion circuit may include a delay circuit that has a plurality of delay devices, the delay circuit outputting a first and second lower phase signals, a latch unit that latches the first and second lower phase signals, a lower counting unit that generates a first and second lower count signals, the lower counting unit generating and outputting a lower difference signal, and a higher counting unit that generates a higher difference signal, subtracts a predetermined number from the higher difference signal, or adds the predetermined number to the higher difference signal, and outputs the higher difference signal after subtraction or addition processing.