Laser point throwing instrument and beam splitting device thereof

The utility model discloses a beam splitting device applied to a laser point throwing instrument. The beam splitting device is characterized by comprising an incident surface, wherein a transmitting area is formed in the center of the incident surface; four reflecting surfaces are arranged on the opposite side of the incident surface beside the transmitting area; four exit surfaces are respectively arranged on the four corresponding reflecting surfaces; incident light beams are reflected to the exit surfaces and exit light beams are perpendicular to the direction of the incident light beams because of the angle setting of each reflecting surface; the included angle between the two adjacent exit light beams is 90 degrees. Because of the arrangement of the beam splitting device provided with a through hole and the four reflecting surfaces, a light beam is divided into five sub light beams by an optical element; and therefore, the five-point throwing can be realized by only one laser tube, the size of the point