The present invention relates to a ball throwing device. The ball throwing device comprises: a power unit such as a battery； a switch which generates electricity in sync with an operation of a switch adapted for driving a motor； a conveyor belt unit which conveys an object by rotation in a similar manner as the conveyor system in a factory； a ball-gathering belt which includes multiple hook-like protruded portions capable of gathering balls, formed at a uniform distance on top of the conveyor belt, wherein the ball-gathering belt is hung on a belt wheel in an endless manner； a driving unit such as an electric motor, which rotates the belt wheel by using an electric motor； a frame portion； a wheel unit which moves a cart； a basket unit which contains balls； and an authentication and control unit which authenticates a ball by using an image sensor capable of recognizing a ball. The authentication and control unit recognizes coordinates of a ball, drawn so as to be recognized by the image sensor once the ball is recognized through a pretreatment process for normalizing the size of the ball into a uniform size and removing unnecessary images, the pretreatment process necessitated by the fact that the size of a ball may look different depending on the distance. Once the authentication and control unit generates an electric signal regarding an angle of the wheel enabling the wheel to face the coordinates, a servomotor integrated with the wheel, which is adapted to move the cart according to the generated electric signal, rotates； the wheel is rotated by the electric motor toward the ball； and upon reaching the ball, the ball is gathered into the basket, and a hole is formed on the bottom of the basket to bring the ball into a pitching machine unit； the ball enters the pitching machine unit below the basket, and a pitching machine； and the ball is ejected by the pitching machine, prompting a pet animal to chase and fetch the ball. Accordingly, the ball throwing device of t
