Gas analyser for measuring two gas components in a measurement gas, - with a first light-emitting diode which emits light with a first wavelength in the range of an absorption line of the one, first gas component, - with a second light-emitting diode which emits light with a second wavelength in the range of an absorption line of the other, second gas component, - with a beam splitter, - with a measurement chamber, through which measurement gas can flow, said measurement chamber being embodied as an elongated hollow body open on both sides and consisting of metal, with two lateral access openings for the measurement gas, - with a measurement detector, - with a reference detector and - with a control and evaluation device for controlling the light-emitting diodes (1, 2) in an alternating manner and for evaluating the signals supplied by the measurement detector and the reference detector to form measurement results for the two gas components, characterised in that - the gas analyser further comprises a rectangular metal block comprising a base, a top surface and four lateral surfaces and a detector block which is made from metal and contains an opening, wherein - the beam splitter is arranged in an intersection region of two bores (17, 18) of the rectangular metal block, which two bores (17, 18) run between the respective opposing lateral surfaces of the rectangular metal block, - the two light-emitting diodes (1, 2) are arranged on two adjoining lateral surfaces and the measurement chamber and the reference detector are arranged on the other two adjoining lateral surfaces of the metal block in each case opposing the bores (17, 18), - the measurement detector is held on the detector block and - the rectangular metal block and the detector block are connected to one another via tension rods and the measurement chamber is clamped between them. - with a first light-emitting diode which emits light with a first wavelength in the range of an absorption line of the one, first gas component, - with a second light-emitting diode which emits light with a second wavelength in the range of an absorption line of the other, second gas component, - with a beam splitter, - with a measurement chamber, through which measurement gas can flow, said measurement chamber being embodied as an elongated hollow body open on both sides and consisting of metal, with two lateral access openings for the measurement gas, - with a measurement detector, - with a reference detector and - with a control and evaluation device for controlling the light-emitting diodes (1, 2) in an alternating manner and for evaluating the signals supplied by the measurement detector and the reference detector to form measurement results for the two gas components, - the gas analyser further comprises a rectangular metal block comprising a base, a top surface and four lateral surfaces and a detector block which is made from metal and contains an opening, wherein - the beam splitter is arranged in an intersection region of two bores (17, 18) of the rectangular metal block, which two bores (17, 18) run between the respective opposing lateral surfaces of the rectangular metal block, - the two light-emitting diodes (1, 2) are arranged on two adjoining lateral surfaces and the measurement chamber and the reference detector are arranged on the other two adjoining lateral surfaces of the metal block in each case opposing the bores (17, 18), - the measurement detector is held on the detector block and - the rectangular metal block and the detector block are connected to one another via tension rods and the measurement chamber is clamped between them.