An object information acquiring apparatus has: a holding unit which holds an object a probe which receives an acoustic wave generated in the object via the holding unit and converts the acoustic wave to an electrical signal a force measuring unit which measures a force applied to the object when the object is held by the holding unit a sound speed acquiring unit which determines a sound speed in the object by using the force measured by the measuring unit and a contact area between the object and the holding unit and a generating unit which generates object information data from the information about the sound speed determined by the sound speed acquiring unit and the electrical signal.
