A photoacoustic imaging apparatus includes a signal processor. The signal processor includes an adding unit configured to add received signals obtained by acoustic wave detecting devices to obtain a summed signal, a normalizing unit configured to normalize the summed signal for each acoustic wave detecting device with reference to an amplitude value in the received signal in the acoustic wave detecting device at the time when a maximum amplitude value in the summed signal is obtained to obtain a normalized signal, a reducing unit configured to subtract the normalized signal from the received signal for each acoustic wave detecting device to obtain a reduced signal in which the amplitude value in the received signal at the time when the maximum amplitude value in the summed signal is obtained is reduced, and an imaging unit configured to generate image data using the reduced signals.