An object information acquisition apparatus includes a holding member, a probe unit, a transducer, a housing, an opposing member, and a separating member. The holding member holds an object. The probe unit scans with respect to the holding member and includes a housing and a transducer positioned to form a space between the transducer and the holding member. The transducer receives an acoustic wave from the object through the holding member and is housed in the housing. The opposing member is provided at an upper position relative to an area that is scannable with the probe unit. The separating member is provided in at least one of the probe unit and the opposing member and having a shape that is changeable. The separating member reduces spreading of a matching liquid that has flowed onto the housing from the space between the transducer and the holding member.
