Composite optical element and optical head device

A composite optical element comprising:

• a single lens having a curved surface shape and acting optically;
• a first resin layer formed on a surface of the single lens;
• and
• a second resin layer formed on the first resin layer, wherein:
• the first resin layer has a diffraction grating of a Fresnel lens configuration on a side of the second resin layer;
• and
• a refractive index of the first resin layer and a refractive index of the second layer are substantially the same value for at least a light beam of one of a light beam of a wavelength λ1, a light beam of a wavelength λ2 and a light beam of a wavelength λ3 (λ1<λ2<λ3) and the refractive index of the first resin layer and the refractive index of the second resin layer are different values for at least a light beam of another one of the light beam of the wavelength λ1, the light beam of the wavelength λ2 and the light beam of the wavelength λ3.