The present invention relates to a laser marker which comprises a level for adjusting the horizontal position of the laser marker, and adjustment rack pivotably fastened to a casing thereof for adjusting the vertical position of the light concentrator thereof, and rotary socket covered by a lens cover to hold a lens for regulating the light of the light concentrator into a light spot or a line of light for projection onto an object. 
Conventionally, carpenters commonly use an ink box to mark lines of workpieces.  When in use, the ink box is retained in position by one person, and the thread of the ink box is pulled by another person and then attached to the workpiece to mark a line thereon.  This type of marking device is inconvenient in use, and it will contaminate the hands of the users and the workpieces easily.