An object information acquiring apparatus comprising: a photoacoustic probe unit including a light irradiating unit configured to guide light from a light source to irradiate an object , and a probe configured to receive a photoacoustic wave generated from the object irradiated with the light by the light irradiating unit, the probe being configured to transmit an ultrasound wave to the object and to receive a reflected wave of the transmitted ultrasound wave; a processor configured to create image information on an internal part of the object based on the photoacoustic wave received by the probe; and a controller configured to control the irradiation with the light from the light irradiating unit, characterized in that the controller is configured to determine whether or not the photoacoustic probe unit is in contact with the object in such a manner that the probe is acoustically matched with the object by using the reflected wave; the controller is further configured to determine a movement of a tissue in the object based on a time required for transmission and reception of the ultrasound wave to the tissue; the controller is further configured to enable the irradiation with the light from the light irradiating unit to be performed when the photoacoustic probe unit is determined as being in contact with the object and the tissue is moving in the direction toward the photoacoustic probe unit or stationary relative to the photoacoustic probe unit ; the controller is further configured to stop the irradiation with the light from the light irradiating unit to be performed when the photoacoustic probe unit is determined as not being in contact with the object , or when the photoacoustic probe unit is determined as being in contact with the object and the tissue is moving in the direction away from the photoacoustic probe unit. a photoacoustic probe unit including a light irradiating unit configured to guide light from a light source to irradiate an object , and a probe configured to receive a photoacoustic wave generated from the object irradiated with the light by the light irradiating unit, the probe being configured to transmit an ultrasound wave to the object and to receive a reflected wave of the transmitted ultrasound wave; a processor configured to create image information on an internal part of the object based on the photoacoustic wave received by the probe; and a controller configured to control the irradiation with the light from the light irradiating unit, characterized in that the controller is configured to determine whether or not the photoacoustic probe unit is in contact with the object in such a manner that the probe is acoustically matched with the object by using the reflected wave; the controller is further configured to determine a movement of a tissue in the object based on a time required for transmission and reception of the ultrasound wave to the tissue; the controller is further configured to enable the irradiation with the light from the light irradiating unit to be performed when the photoacoustic probe unit is determined as being in contact with the object and the tissue is moving in the direction toward the photoacoustic probe unit or stationary relative to the photoacoustic probe unit ; the controller is further configured to stop the irradiation with the light from the light irradiating unit to be performed when the photoacoustic probe unit is determined as not being in contact with the object , or when the photoacoustic probe unit is determined as being in contact with the object and the tissue is moving in the direction away from the photoacoustic probe unit. <EOS>