A fixing element of plastic includes a foot part for insertion into an oblong hole of a carrier plate. The foot part includes a head and a shaft. The fixing element can be locked in the oblong hole after the insertion of the head by a quarter turn. The shaft includes a middle strut connected to the head. A shank is formed on each of the two edges of the middle strut at right angles and in opposite directions. A countershank is formed on each of the edges of the middle strut in opposite directions. The shank is elastically bent towards the middle strut during the screwing in of the shaft through the edge of the hole and after a quarter turn returns to its original position. Pressing ramps are formed on two outer ends of the head to prevent a rotation in the opposite direction.