The present invention employs an object information acquiring apparatus including: an acoustic detector that receives acoustic waves generated from an object at a plurality of measurement positions and converts the acoustic waves to a plurality of signals a shape information acquirer that acquires surface shape information of the object a signal estimator that estimates a target signal derived from an acoustic wave generated at a specific position from the plurality of signals based on the surface shape information a reducer that reduces the target signal estimated by the signal estimator and a characteristic information acquirer that acquires characteristic information on the inside of the object using the plurality of signals in which the target signal is reduced by the reducer.
