An object information acquisition apparatus comprises an irradiating unit configured to irradiate an object with light; a plurality of detecting units configured to receive an elastic wave generated within the object irradiated with light, and convert the elastic wave to a received signal; a distribution acquiring unit configured to acquire a light intensity distribution within the object irradiated with light; a setting unit configured to select a minimum block unit in which light intensity is greater than or equal to a predetermined threshold value, using the light intensity distribution; and a generating unit configured to generate object information of the minimum block unit selected by the setting unit, using the received signal.