There is provided a lens system (10) that projects projected light onto a screen (6) and includes, in order from the screen (6) side thereof, a first lens (L11) that is a meniscus-type lens with negative refractive power and is convex on the screen (6) side; a second lens (L12), a third lens (L13) and a fourth lens (L14) that are meniscus-type lenses with positive refractive power and are concave on the screen (6) side. In addition, the effective diameter of a concave surface (S6) of the third lens (L13) is larger than the effective diameter of the concave surface (S3) of the second lens (L12), the effective diameter of the concave surface (S8) of the fourth lens (L14) is larger than the effective diameter of the concave surface (S6) of the third lens (L13), and part of the convex surface (S7) of the third lens (L13) and part of the concave surface (S8) of the fourth lens (L14) are located in a shared space along the optical axis.