The present invention relates to a power amplifier; and, more particularly, to a Doherty power amplifier. The power amplifier includes at least one carrier amplifier; at least one peaking amplifier arranged in parallel with the carrier amplifier in such a manner that the carrier amplifier and the peaking amplifier collectively operate as a Doherty amplifier; a plurality of input matching circuits, at least one of which is respectively connected to an input ends of the carrier amplifier and the peaking amplifier; at least one impedance control circuit, each of which is connected to an output end of each carrier amplifier for controlling a load line impedance of the said each carrier amplifier; at least one output matching circuit directly or indirectly connected to output ends of the impedance control circuit and the peaking amplifier; and at least one first delay circuit for matching delays between the carrier amplifier and the peaking amplifier. The present invention provides an improved Doherty power amplifier capable of achieving a further miniaturization and integration while maintaining an advantage in terms of efficiency and linearity of a Doherty power amplifier by employing an improved output and input matching method, and capable of operating more similar to the ideal operation of a Doherty power amplifier by applying an improved input power division method thereto.