A subject information acquisition apparatus of the present invention acquires a sound speed in the subject by using a signal outputted from a first probe when a first probe receives an elastic wave, a member-to-member distance information between a first holding member and the second holding member, an amount of deformation of a first holding member measured by a first holding member deformation amount measuring unit, an amount of deformation of a second holding member measured by a second holding member deformation amount measuring unit, position information of the first holding member deformation amount measuring unit, and position information of the second holding member deformation amount measuring unit.
