there is provided a lens module , including : a first lens having positive refractive power , an object - sided surface thereof being convex ; a second lens having negative refractive power , an image - sided surface thereof being concave ; a third lens having positive refractive power ; a fourth lens having negative refractive power , an image - sided surface thereof being convex ; and a fifth lens having negative refractive power , an image - sided surface thereof being concave , wherein the fourth lens satisfies conditional expression 1 , f ⁢ ⁢ 4 f & lt ; - 3 . 0 where f is an overall focal distance of an optical system and f4 is a focal distance of the fourth lens .