A measuring head for the determination of the concentration of a paramagnetic gas in a gas sample has first and second housing parts (21, 2) made of a steel alloy for accommodating a magnet coil body (4, 5) each. The magnet coil bodies extend concentrically around the central axis of each housing part (21, 2). Metallic bars (31, 3), which are used as magnet poles for the measuring head, are located at spaced locations with a defined air gap in the assembled state of the measuring head. The bars are arranged in the center of the measuring head in the area of the central axis of the housing parts (21, 2). A sample gas cuvette support (6) is provided in the air gap between the housing parts (21, 2) for positioning a sample gas cuvette holder (1). The sample gas cuvette support (6) is provided with a gas inlet and gas outlet (8, 81).