[Problem] In the discrimination of biological tissue using a photo acoustic analysis method, to enable discrimination with good accuracy of luminal tissue shown in an ultrasonic image or tissue that includes collagen or fat shown in an ultrasonic image. [Solution] In the present invention, in the discrimination of biological tissue using a photo acoustic analysis method, the following means are provided: a determination means (29) for determining whether a luminal region corresponds to one from among a blood vessel region, a lymphatic vessel region, and a nerve region, or whether the tissue region shows a tissue including collagen and/or fat； and an image synthesizing means (30) for synthesizing ultrasonic images in which luminal regions and tissue regions are color coded in accordance with such determination results, and for displaying such synthesized images. The determination means (29) performs determination on the basis of the presence or absence of peak data in photo acoustic data related to each of a plurality of measurement light for which the magnitude correlations with respect to the absorption coefficients of hemoglobin, fat, water, and collagen are mutually different.
