Provided is a compact high frequency power amplifier having a high degree of freedom of design with respect to a gain fluctuation immediately after start-up of an amplifier. The high frequency power amplifier includes a speed-up circuit that transiently increases a reference voltage during rise of a control voltage to increase an amount of bias supplied to an amplification transistor from a bias circuit. The speed-up circuit includes a capacitor and an overshoot control circuit. The overshoot control circuit determines an increasing amount of the reference voltage when the reference voltage is transiently increased according to a charge amount charged in the capacitor, and the overshoot control circuit also determines a time constant in charging and discharging the capacitor.