The techniques of silicon micromaching have been used to develop a miniature infrared sensor with tunable wavelength selectivity for application in infrared spectroscopy. The infrared sensor consists of a tunable interference filter in front of a wide-band detector. The applicable spectral bandwidth ranges from 1.5 to 7.5 μm. The resolution is better than 25 nm over the whole range. The wavelength tuning and parallelism control of the mirrors is carried out by electrostatic forces, varying the voltage at the integrated disk capacitors. The transmitted infrared radiation is absorbed in a black gold layer, the rising temperature being measured by a thermopile consisting of 80 Si-Ni thermocouples. This device is expected to find application as an emission monitor for liquids and gases.