The present invention provides a semiconductor device that can adjust signal frequency bandwidths and consumption currents to be appropriately increased or reduced in source-follower amplifiers in all stages. The semiconductor device is comprised of a source-follower amplifier including a driver transistor D1, and a load transistor L1 that is connected to the driver transistor D1 and driven variably depending on a signal inputted to the driver transistor, wherein a gate of the load transistor L1 is applied with a variable bias voltage. The semiconductor device 1 is further comprised of a source-follower amplifier including a driver transistor D2, and a load circuit (load transistor L2) that is connected to said second driver transistor and driven variably depending on a signal outputted from the second driver transistor D2, wherein a gate of the load transistor L2 is applied with a variable bias voltage to vary a resistance value of the load transistor L2.