A ring zonal phase correction lens made of resin is provided with a
refraction face structurally formed on at least one of a first lens face
and a second lens face. The refraction face includes three or more ring
zonal shaped refraction curved surfaces which are formed to be adjacent
to each other through step portions formed in an optical axis direction
for correcting a phase of a laser beam emitted from a laser by respective
ring zonal shaped refraction curved surfaces. The step portion is formed
such that a lens thickness of an outer ring zonal shaped refraction
curved surface becomes thicker than that of an inner ring zonal shaped
refraction curved surface and the step portion is formed at a half or
more outer area of an effective radius of the refraction face.