PURPOSE: To run an examining device even in a small-diameter pipe line of town gas or the like to examine the inside of the pipe by not attaching a wheel driving device to an examining car body but setting this device on the outside of the pipe and driving wheels with a flexible rotation transmitting body.

CONSTITUTION: Driving wheels 1 of tyre type or the like and freely rotating wheels 2 are attached to an examining device A and are driven by a flexible linear rotation transmitting body 5 and a wheel driving device 4. Shafts of driving wheels 1 and freely rotating wheels 2 are attached approximately orthogonally to spiral around the center of a pipe 3 and are moved freely in the diametral direction of the tube. A television camera and an electromagnetic defect sensor 6 are attached to the examining device A. The examining device A is revolved on its axis and is moved in the pipe 3 to examine corrosion and defects in the pipe 3. Since the driving device is provided on the outside of the pipe in this manner, the examining device A is made small-sized and is applied to even a samll-diameter pipe and a little bent pipe.