Disclosed is a device and method for mounting a leap block capable of automatically adjusting the mounting direction of the leap block. The leap block mounting device comprises: a block stand (70) fixedly mounted to one end of a blocking device frame (10) and configured to support a leap block (5) so that the leap block (5) is rotatable in a horizontal direction; the leap block (5) in which a support (82) rotatably supported by the block stand (70) is formed in the center, and a first magnetic body (84) is mounted in one direction; and a leap block mounting unit (30) to which a second magnetic body (38) that couples with the first magnetic body (84) by magnetic force is mounted in one direction, and which rotates in the horizontal direction and couples with the leap block (5) in a fixed direction.