An optical system of a projection television receiver for projecting pictures from a picture tube onto a screen, comprising a fluorescent face constituting the tube face of the receiver tube having a nonspherical shape in such a direction as to compensate the curve of the image face of the projected picture on the screen, and further comprising lenses arranged from the screen side to the tube face of the picture tube in the order of:(A) a first lens having relatively weak power (reciprocal of focal distance) and having a nonspherical shape at least at one face;(B) a second lens having relatively strong positive power;(C) a third lens having relatively weak power and having a nonspherical shape at least at one face; and(D) a fourth lens having relatively strong negative power and having a concave shape at the face of the screen side.