Abstract: A method and apparatus for detecting the motion variation of a baseball is described, the apparatus including: a plurality of sensors between a beginning point and an ending point of motion, the sensors detecting the position variation of a pitched baseball using two-dimensional coordinate values; and a controller for synchronizing the two-dimensional coordinate values output from the sensors to an inside clock being input the synchronized values, and for calculating the speed of a baseball according to the distance between predetermined sensors and the detected two-dimensional coordinate values. Accordingly, the present invention can detect a curving degree and speed variation of a baseball. Particularly, in the case that the lattice structures of the sensors are closely placed in the vicinity of a home plate, the user can minutely measure the motion variation of a baseball.