A drive amplifier having improved linearity while being characterized by low current consumption. The drive amplifier includes first and second transistors having a gate to which first and second differential Radio Frequency (RF) voltages are respectively input; a third transistor which has a drain connected to a drain of the second transistor and a source connected to the gate of the first transistor, and a drain-source current which increases with an increase in the second differential RF voltage; and a fourth transistor which has a drain connected to a drain of the first transistor and a source connected to the gate of the second transistor, and a drain-source current which increases with an increase in the first differential RF voltage.