Provided is an inspection robot that is self-propelled on piping, measures moisture contained in a lagging material using a mounted inspection device, for example, a neutron moisture meter, and detects risk of corrosion. The inspection robot includes a main frame 1 including a recessed part 17 fit onto an outer circumferential surface of piping P, a main frame drive mechanism (first drive mechanism) D1 that causes the main frame to advance / retract in an axis direction of the piping, a revolving member 32 supported in an advanceable / retractable manner along an arc-shaped locus in the recessed part of the main frame, a revolving member drive mechanism (second drive mechanism) D2 that moves the revolving member, and an inspection device mounted on the revolving member.