Disclosed herein is an amplifier including a voltage follower circuit having differential input terminals and an output terminal fed back to a first one of the differential input terminals, the voltage follower circuit being configured to amplify an input signal inputted to a second one of the differential input terminals and output the amplified signal from the output terminal; a first current source configured to supply a predetermined current to the voltage follower circuit; and a second current source configured to supply current to the voltage follower circuit when a potential difference between the second one of the differential input terminals and the output terminal is equal to or higher than a predetermined value.