PURPOSE: To provide an infrared spectroscopy probe suitable to usage for both a fluid sample and a solid sample by providing a cylindrical sheath which is opaque to radiation of infrared ray, and which has a cylindrical tip part for sampling having a terminal edge and infared reflection coating.

CONSTITUTION: For a probe 1, its end part is held in a chuck 2 of a connection member 3 provided with plugs 4, 5 for connection to an infrared ray source of a spectroscope and an infrared recording device. The probe 1 has a sheath 6 which is opaque to infrared ray, and which has a pair of optical fibers 7, 8 for transmitting infrared ray. Inside the connection member 3, the optical fibers 7, 8 are separated from each other, and combined with plugs 4, 5. At an end part of the probe 1 closer to a sample, a detachable cylindrical sleeve 10 for forming a sampling zone is installed. This sleeve 10 has gold-coated infrared reflection surface at a terminal edge and inner side of it, and the optical fibers 7, 8 end a little before the terminal edge to form a recessed plate 11 for sampling.