Provided are: an
optical pickup device and optical information recording /
reproduction device provided with an objective lens capable of improving temperature characteristics and
wavelength characteristics while making it possible to support three types of
optical disc, namely Blu-
ray Discs, DVDs, and CDs, with a shared objective lens; and an objective lens suitable therefor. A first optical-path-difference creation structure, in which at least a first basic structure and second basic structure are superimposed, reduces a step difference in the optical-axis direction, thereby keeping the
diffraction efficiency from decreasing upon
wavelength changes. Furthermore, when the
wavelength of incident light increases,
spherical aberration from the aforementioned first basic structure and second basic structure changes in the direction in which more correction is needed; thus, when the index of
refraction of the objective lens changes as a result of an increase in the temperature of the
optical pickup device, the fact that the wavelength of the
light source also increases as a result of the increase in ambient temperature is utilized to correct spherical-aberration degradation due to the change in the index of
refraction of the objective lens.