A closing device is provided for a container of a respirator with two container shells (2, 2′) joining each other at front surfaces, with at least one tightening strap (4), which encloses a part of a container shell outer surface located at right angles to the front surfaces. Two holding elements (5, 5′) are each provided with a recess (6, 6′) and are formed at the free ends of the tightening strap (4). A closing element (7) is formed in a U-shaped pattern with two legs (8) and meshes with each recess (6, 6′) of the holding elements (5, 5′). The legs (8) of the closing element (7) can be pulled out of the recess (6, 6′) of the holding elements (5, 5′) to take off the tightening strap (4).