A desk-top type infrared radiation moisture measuring apparatus is of a type in which the moisture in a specimen is exposed to a measurement light easily absorbed into water and to at least one reference light not noticeably absorbed into water and calculation is performed to determine the moisture in the specimen on the basis of both the measurement light and the reference light, reflected from the specimen. The apparatus comprises a turntable on which the specimen is placed and which is exposed to both the measurement light and the reference light from above at a portion away from the center thereof, and a drive source for driving the turntable into rotation. The measurement is carried out while the turntable is being rotated.