Abstract: A pair of front rotary wheels are disposed so that they hold therebetween a frame extending in the direction in which a ball is thrown. A pair of rear rotary wheels are disposed rearwardly of the front rotary wheels and with the frame held therebetween. These front and rear rotary wheels are operatively connected together by operatively connecting devices. When a ball is fed in from the rear end of the frame, it is nipped between the outer peripheral surfaces of the pair of rear rotary wheels and thrown forward and then it is nipped between the outer peripheral surfaces of the front rotary wheels and thrown forward. An annular bracket is fitted on the frame in its intermediate portion between the front and rear rotary wheels and is attached to the frame. The annular bracket are pivotally supported at its right and left outer sides on the support block, and the operatively connecting devices are disposed within the annular bracket.