PROBLEM TO BE SOLVED: To miniaturize a device configuration and improve operability for an operator and a user in photoacoustic tomography.SOLUTION: A subject information acquisition device includes: a photoacoustic probe including a light emission part for guiding light from a light source to a subject, and a probe for receiving a photoacoustic wave generated from the subject irradiated with light by the light emission part, transmitting an ultrasonic wave to the subject, and receiving a reflection wave a processing part for generating image information inside the subject based on the photoacoustic wave received by the probe and a control part for controlling the irradiation of the light from the light emission part. When a state in which the light from the light emission part is irradiated to the subject, and the photoacoustic probe is in contact with the subject so that the probe makes acoustic matching with the subject is a first contact state, the control part determines whether or not the photoacoustic probe is in the first contact state using the reflection wave, and if it determines that the photoacoustic probe is in the first contact state, it enables the irradiation of the light from the light emission part.SELECTED DRAWING: Figure 1
