An object information acquiring apparatus is used that has a receiver receiving acoustic waves propagating through an object at a plurality of measurement positions and a processor acquiring on a two-dimensional flat surface projection image data obtained by projecting a distribution of property information relating to a measurement target within the object, wherein the processor acquires intensity-dependent three-dimensional image data within the object and non-intensity-dependent three-dimensional image data within the object, based on the acoustic waves, determines voxel coordinates projected onto the two-dimensional flat surface, based on the intensity-dependent three-dimensional image data, and acquires the projection image data, based on values of the non-intensity-dependent three-dimensional image data.
