Disclosed is a small lens system including a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially arranged from an object, wherein the first lens has a convex surface facing the object, the second lens has a convex surface facing the object and a positive refractive power, the third lens has a positive or negative refractive power, the fourth lens has opposite surfaces convex toward an image, the fifth lens has opposite surfaces convex toward the image, the sixth lens has at least one aspherical surface and is configured such that the object-side surface of the sixth lens is convex in the vicinity of an optical axis, and the seventh lens has at least one aspherical surface and is configured such that at least one inflection point is provided on the aspherical surface of the seventh lens.