A differential amplifier comprises terminals for receiving signals, and outputting a signal, and differential pairs, each having an input and output pair, the differential pairs supplied with currents, respectively, a load circuit connected to the differential pairs, an amplifier stage for receiving input, a signal of at least one connection node of the load circuit and output pairs of the differential pairs, the amplifier stage having an output connected to a terminal and a connection switching circuit for controlling switching between connection states of a first differential pair and second differential pair.