In a color television camera, a color separation optical system includes a first relay lens behind a taking lens of the camera, color separation optical elements such as prism blocks or dichroic mirrors, and a set of second relay lenses. Image pick-up tubes for three colors are provided behind the second relay lenses. The pick-up tubes are mounted in coil assemblies. Each coil assembly is provided with a rotating device for conducting a position adjustment of the tube with respect to the associated second relay lens to make perfect registration between images of the three tubes. A focus adjusting device for conducting a focus adjustment between each second relay lens and the associated image pick-up tube is provided in each second relay lens. The focus adjusting devices are operable from outside the camera for sliding the second relay lenses in the direction of their optical axes.