To provide a novel information processor, an entertainment device, and a man-machine interface system allowing an input to a computer or a game machine in a real time using a stroboscope.

A golf game system 10 includes a game machine 12 golf club type input device 14 of the information processor, an imaging unit 28 is stored in an inside of a housing 16 of the game machine, and an image sensor 40 and an infrared light emitting diode 42 are provided in the imaging unit 28. A prescribed range in an upper side of the imaging unit is irradiated intermittently with infrared rays by the infrared light emitting diode, and the image sensor photographs thereby a reflecting body provided in the golf club type input device moving within the range. A stroboscopic image of the reflecting body is processed by this manner to calculate a speed of the input in the game machine. The input is allowed to be imparted to the computer or the game machine in the real time using the stroboscope.