An objective lens for an endoscope has an object-side lens element including a plane-convex rod lens and an image-side lens element including a biconvex lens arranged at the image-side end of the objective lens. The object-side lens element includes a plane-convex first lens and a biconcave second lens which form a front lens and are arranged in this order on the object side of the plane-convex rod lens forming a third lens. As viewed from the object side, the image-side lens element includes a biconvex fourth lens, a concave-plane fifth lens and a biconcave sixth lens which are arranged in this order on the object side of the biconvex lens that is arranged at the image-side end of the objective lens and forms a seventh lens.