An objective lens, an optical head, an optical disk apparatus and an information processing apparatus which can suppress deterioration of a focal spot caused by a drop in the diffraction efficiency are provided. An inner circumference area (111) and an outer circumference area (113) converge a laser beam having an order of diffraction with which diffraction efficiency is highest, out of laser beams having a wavelength λ1 which are diffracted by the inner circumference area (111) and the outer circumference area (113), on an information recording surface of a first information recording medium; the inner circumference area (111) and a mid-circumference area (112) converge a laser beam having an order of diffraction with which diffraction efficiency is highest, out of the laser beams having a wavelength λ2 which are diffracted by the inner circumference area (111) and the mid-circumference area (112), on an information recording surface of a second information recording medium; and the diffraction efficiency of the laser beam having the wavelength λ2, which is diffracted by the mid-circumference area (112) and converges on the information recording surface of the second information recording medium, is greater than the diffraction efficiency of the laser beam having the wavelength λ1 which is diffracted by the mid-circumference area (112), and converges on the information recording surface of the first information recording medium.