An amplifier circuit of envelope tracking scheme has a timing adjusting unit having a finite number of adjustment values for adjusting time by which the output is delayed from the input, and capable of adjusting a time difference between an input signal and a power supply voltage which reach an amplifier, by making a selection from the adjustment values; a test signal output unit capable of repeatedly sending out a test signal serving as the input signal at predetermined cycles; and an adjustment value determining unit sequentially measuring output power for m (≦k) periods from the amplifier while changing an adjustment value of the timing adjusting unit to a different value every k periods of the test signal, searching for an adjustment value at which a total sum of the output power form periods is maximum, and setting the adjustment value on the timing adjusting unit.