An imaging lens includes negative first lens, negative second lens, third lens of a plano-convex shape having a convex surface directed toward an object side or of a positive meniscus shape having a convex surface directed toward the object side, and a fourth lens of a plano-convex shape having a convex surface directed toward an image side or of a positive meniscus shape having a convex surface directed toward the image side, which are arranged in this order from the object side. Further, the following conditional formula (6) is satisfied: 0.75≦(R8−R9)/(R8+R9)≦1.0  (6), where R8: a curvature radius of an object-side surface of the fourth lens, and R9: a curvature radius of an image-side surface of the fourth lens.