An image signal input circuit includes an input terminal configured to receive an image signal, a clamp circuit configured to hold a sink chip voltage contained in the image signal to be a constant value, a level shift circuit that includes a first emitter follower having a first transistor and a first current source, and a second emitter follower having a second transistor and a second current source, a base of the second transistor being connected to an emitter of the first transistor, and that is configured to shift a level of the sink chip voltage which is held constant, and an electric current source configured to attract a base current of the first transistor.