Provided is an object information acquiring apparatus including: a holding unit that holds an object a probe that receives an acoustic wave that propagates from the object a housing that constitutes a holding container a matching solution that is filled inside the holding container and a pressure adjustment unit including a liquid quantity adjustment section that adjusts the quantity of the matching solution, and a distance adjustment section that adjusts the distance between the holding container and the object, wherein the pressure adjustment unit performs a first compression which increases a pressure applied to the object to a predetermined pressure value, and then performs a second compression which maintains the predetermined pressure value, while decreasing the liquid quantity inside the holding container.
