Abstract: A device for detecting the presence of a golf ball G in a ball-receiving cup comprising a flag pole 1 having a tubular lower portion 2 dimensioned to be received within a standard ball-receiving cup C and supporting four photointerruptors each comprising an infrared emitter 5 and a corresponding photodetector 5A, with the beams from the emitters 5 passing through opening 6 in the tubular portion 2 and being spaced at 90.degree. intervals around the periphery of the tubular portion 2 so that the four quadrants of the cup C are within the fields of the photointerruptors. When a golf ball G enters the cup C, the infrared beam from one of the emitters 5 is reflected from the surface of the golf ball G and i s received by the corresponding photodetector to cause a change in the state of the photodetector which in turn causes a display 3 to be illuminated to indicate that a golf ball G has ended the cup C.