An objective lens for endoscopes has a front lens unit and a rear lens unit with an aperture stop between them. The front lens unit includes a first lens element with negative refracting power and a second lens element with positive refracting power, and the rear lens unit includes a third lens element with positive refracting power, a cemented lens component of a fourth lens element with positive refracting power and a fifth lens element with negative refracting power. The objective lens satisfies the following conditions: −2