To provide a measuring device for a cylindrical material for measuring the outside diameter, straightness, and cylindricity easily and with high accuracy without defect such as scar in a material to be measured.

The measuring device 10 for a cylindrical material is formed by a material support table 14 for supporting a material W to be measured, a material receiving part 20 provided with a hole formed with a diameter larger than the diameter of the material W to be measured, and adapted to jet gas from the inner peripheral part of the hole toward the center, and a pneumatic-to-electric transducer 22 for converting a change in back pressure of jetted gas to an electric signal. The measuring device 10 finds the outside diameter of the material W to be measured according to a signal from the pneumatic-to-electric transducer 22 when the material W to be measured is inserted in the hole of the material receiving part 20.