an input terminal configured to input an input signal having a band signal to be amplified;

first to ith blocks including a single resonator and an amplifier wherein each single resonator of the first to ith blocks has first to ith resonance frequencies (first resonance frequency<second resonance frequency< . . . <ith resonance frequency) included within a band of the band signal to be amplified and extracts a signal having the resonance frequency of each single resonator as a center frequency from the band signal, and each amplifier of the first to ith blocks amplifies a signal extracted by each single resonator;

a divider configured to divide the input signal having the band signal to be amplified for each resonator of the first to ith blocks;

a combination section configured to combine the signals which have passed through the first to ith blocks to obtain a combined signal; and

an output terminal configured to output the combined signal,

wherein a jth (j: an integer between 1 and i−1) block includes a phase adjustment section which provides an output signal of the jth block with a phase difference within a range of {(180±30)+(360×n)} degrees (n: an integer of 0 or greater) from an output signal that passes through a (j+1)th block.