PURPOSE: To obtain the titled lens which is compact constitution with less short range variation of aberration, by constituting specific three lens groups, and satisfying specific conditions.

CONSTITUTION: A first lens group consists of a first and a second lenses of positive lenses, a third lens of a negative lens and a fourth lens of a positive lens, a second lens group consists of a cemented positive lens which has joined a fifth lens of a positive lens and a sixth lens of a negative lens, a third lens group consists of a cemented negative lens which has joined a seventh positive lens and a eighth negative lens, and a ninth lens of a positive meniscus lens, and they satisfy expressions. In the expressions, (f), f1,2, f1,2,3,4, vIP and vIN, ri and ni denote a focal distance of the whole system, a composite focal distance extending from the first lens to the second lens, a composite focal distance extending from the first lens to the fourth lens, the average values of Abbe numbers of the positive and negative lenses in the first lens group, a radius of curvature of an i-th surface from an object side, and a refractive index of d-line of an i-th lens, respectively. In such a way, the titled lens becomes compact, and various aberrations can be corrected satisfactorily.