To provide a wide-angle lens improved in an optical performance without extending a total length of a lens system.

An aft group lens 20 arranged at an image surface side of an aperture STO is constituted of four lenses of a positive lens 21, a negative lens 22, a positive lens 23, and a positive lens 24 in this order from the object side. A wide-angle lens 5 satisfies each of the following conditional expressions when a focal distance of the entire lens system is expressed by f, a composite focal distance of the aft group lens 20 by f20, a focal distance of the positive lens 24 by f24, a refractive index of the positive lens 21 by N21, and a refractive index of the negative lens 22 by N22, respectively, '1.1<f20/f<1.8', '1.2<f24/f<2.4', 'N21>7.1', and 'N22>1.8'. When the focus is adjusted, only the positive lens 24, which is positioned nearest to the image side among the aft group of lenses, is moved on the optical axis. Moreover, expressing a surface distance between the positive lens 24 and the positive lens 23 by d when focused on an infinitely distant object, a conditional expression '0.2<d/f<0.4' is satisfied.