A phantom used for calibrating an object information acquiring apparatus that irradiates light into an object and acquires characteristic information inside the object based on an acoustic wave propagated from the object, the phantom comprises a base material and a simulated tissue portion that simulates a three-dimensional structure of a tissue inside a living body, wherein the simulated tissue portion is disposed inside the base material, and has a simulated layer, which is a layer simulating optical characteristics of the tissue inside the living body, on the surface thereof.
