To provide a ball sensor of simple structure and high durability, not affected by the influence from the other parts in the display for the contact of a ball, surely sensing the contact of the ball, and hardly failed by the repeated contact with the ball.

A ball sensor comprises a housing 11, a sponge body 12 stored in the housing 11 and discharging the air by the impact by the contact of a ball 30, a soft film body 13 covering a front surface of the sponge body 12 and mounted on a surface of the housing 11, and an air current sensing switch 14 connected to a rear surface of the housing 11, sensing the gas from the sponge body 12 when the ball 30 is contacted with a target, and generating an electric signal, and a plurality of ball sensors are mounted on the predetermined positions of the target in a state that the soft film bodies 13 are directed to a play zone side.