An object information acquiring apparatus comprises an irradiating unit which irradiates light on an object a holding member which includes a light-absorbing member whose optical characteristics with respect to irradiated light are known and which holds the object a detector which detects acoustic waves generated by tissue in the object and the light-absorbing member due to light irradiation and a computing unit which calculates optical characteristics of the tissue in the object and the light-absorbing member by using the detected acoustic waves and which corrects the optical characteristics of the tissue in the object by using the calculated optical characteristics of the light-absorbing member and the known optical characteristics.
