PURPOSE: To obtain the inexpensive lens which may be used for information reading of a video disc and is corrected of spherical aberrations and astigmatisms by decreasing its size and weight, increasing its numerical aperture and maintaining a high resolving power.

CONSTITUTION: The 1st group is constituted by a convex meniscus lens 1 of which the convex face is directed to the image plane, the 2nd group by a convex meniscus lens 2 of which the convex face is directed to the 1st group, the 3rd group by a biconcave lens 3 of which the concave face on the stronger side is directed to the 2nd group, the 4th group by a biconvex lens 4 and the 5th group by a convex meniscus lens or planoconvex lens 5 of which the convex face is directed to the 4th group by leaving an air spacing. These satisfy the various conditions based on formulas 1W9. The formulas 1W5 indicate the distribution of the diopters of the respective lenses, the formulas 6, 7 the conditions necessary removing spherical aberrations to provide sinewave conditions and removing coma aberrations, and the formulas 8, 9 the conditions necessary for negating and balancing the astigmatisms produced in the 1st group and the 2nd group. Here, (f) is the combined focal length of the lens system, R4WR9 are the radii of curvature, D4, D8 are axial spacings, D7 is center thickness and N4 is refractive index.