Abstract: A cage structure for restraining primates includes a bottom of rectangular ground plan and formed by rods or tubes, side walls surrounding the bottom, and a ceiling. A cage structure of this type is to be manufacturable in any desired size and at low an expenditure as possible. The cage develops only low levels of noise. To this end, only one of the side walls, i.e., the front wall, is formed by rods or tubes, while the remaining three side walls and the ceiling are made of concrete or brickwork having their interior surfaces smoothed. The wall opposite the front wall, i.e., the rear wall, is displaceable towards and away from the front wall. At least one side wall and the ceiling incorporate inspection panes made of bullet-proof glass.