Abstract: A fixed-focus lens including a first lens group, a second lens group and a third lens group, which are arranged in sequence from an object side to an image side, is provided. The first lens group has a negative refractive power and includes three lenses arranged from the object side to the image side. The lens, closest to the object side, of the first lens group is an aspheric lens. The second lens group has a positive refractive power and includes two lens arranged from the object side to the image side. The third lens group has a positive refractive power and includes six lenses arranged from the object side to the image side. Refractive powers of the lenses of the third lens group in sequence from the object side to the image side are negative, positive, negative, positive, positive and positive.