Device for marking out center line on spare part

The invention discloses a device for marking out a center line on a spare part. The device comprises a base plate, a vertical fixed bracket and a movable bracket which are arranged on the base plate, as well as a guiding shaft of which two ends are connected onto the fixed bracket and the movable bracket, wherein scales are arranged on the guiding shaft; a scratch awl is connected onto the guiding shaft; the movable bracket is connected with the base plate in a horizontal reciprocating movement manner; the guiding shaft is connected with the fixed bracket and the movable bracket in a vertical reciprocating movement manner; the scratch awl is connected with the guiding shaft in a horizontal reciprocating movement manner; the scratch awl is further connected with the guiding shaft in a forward and backward rotating manner. According to the invention, the scratch awl can move in the horizontal direction and the vertical direction; the rotation of the scratch awl in the horizontal direction and the vertical direc