A security device for a door is disclosed which includes a holding element fixed to a stud of a room wall in a manner to shear the stud upon movement of the holding element toward the inside of the secured room. A locking means comprised by the holding element extends through the wall into the interior of the secured room, and a high strength security element bridging the handle-equipped edge of the door is releasably fastened at one end to the locking means and is received at its opposite end so as to extend along the surface of the door secured thereby.