a varifocal lens which uses an interface between a first fluid and a second fluid that are mutually immiscible , as a light refracting surface , includes : a sealed vessel in which a first chamber into which the first fluid is filled is connected via an opening to a second chamber into which the second fluid is filled ; and an elastic deformation section which is provided in elastically deformable fashion in a portion of a partition wall that divides the first chamber and the second chamber in the sealed vessel and which deforms in contact with both the first fluid filled into the first chamber and the second fluid filled into the second chamber , wherein : a lens section having the interface is formed in the opening , and a focal length of the lens section is changed by causing the interface to deform through altering volumes of the first chamber and the second chamber in mutually opposite directions by deformation of the elastic deformation section .