An optical imaging lens includes a plurality of lens elements arranged in the given order from an object side to an imaging side. Each of the lens elements has a refracting power, an object-side surface facing toward the object side and an image-side surface facing toward the image side. The lens elements include a first lens element closest to the object side, a second lens element second closest to the object-side, a third lens element having a positive refracting power, and a fourth lens element having its object-side and image-side surfaces being aspheric. The object-side surface of the first lens element has a concave portion in the vicinity of the optical axis. The third lens element has at least one of the object-side and image-side surfaces being aspheric.