Debug.Drawline position is slightly over the clicked position

When I draw a line to the hit point by raycasting, it is drawn slightly upper position constantly than where the mouse button is clicked. It is also same when I use 'DrawRay' instead.

Did I miss something in the code below? Thanks for any of your help in advance.

     if (Input.GetMouseButton(0))
     {
         Ray ray;
         RaycastHit hit;

         Vector3 vt = Input.mousePosition;
         ray = Camera.main.ScreenPointToRay(vt);

         var lm5 = (1 << layMan);

         if (Physics.Raycast(ray, out hit, float.MaxValue, lm5))
         {
             Debug.DrawLine(transform.position, hit.point, Color.yellow, 1.5f);
         }
     }

PS. You can see the yellow line upper than the center point that I clicked in the below picture.

http://i.imgur.com/z4ruLLA.png