In a photoacoustic image generation apparatus for generating a photoacoustic image of a subject including an interventional instrument for each scanning plane, there are provided: means for generating a reflected acoustic wave image of the subject for each scanning plane； means for detecting a change in a photoacoustic image on an observation scanning plane, which is generated as an image, from a plurality of photoacoustic images regarding the observation scanning plane； means for detecting a change in a reflected acoustic wave image on the observation scanning plane from a plurality of reflected acoustic wave images regarding the observation scanning plane； determination means for determining whether or not a distal end of the interventional instrument is present on the observation scanning plane based on the change in the photoacoustic image and the change in the reflected acoustic wave image； and notification means for sending notification of a result of the determination.
