A frequency multiplier includes an input terminal, an output terminal, a first transistor having a first gate to which a radiofrequency signal is input from the input terminal, a first drain from which an output signal is issued to the output terminal, and a first source, a second transistor having a second gate, a second source to which the radiofrequency signal is input from the input terminal, and a second drain from which an output signal is issued to the output terminal, and a stabilizing resistor which is a resistor connected to the second gate, wherein no resistor exists on the path for the radiofrequency signal, and wherein the stabilizing resistor suppresses a reflex gain produced by the second transistor.