In a color separation prism system for a color television camera, a bias light source is located at a position substantially displaced from one or the other of the two intersections of (i) a plane including the optical axis of the taking lens of the camera and perpendicular to the plane including the optical axes of the three color light beams incident to the pick up tubes and (ii) the two parallel edges of a prism block formed by the entrance face thereof to which the light from the taking lens of the camera is incident and the upper and lower parallel faces of the prism block parallel to the plane including the optical axes of the three color light beams. The color separation prism system is particularly suitable for use in a system in which the refractive index of the glass constituting the prism blocks is as high as 1.7.