PURPOSE: To inspect the abrasion state of the texture by measuring an electric resistance value given by a belt section part and comparing the resistance value with a specific resistance value corresponding to a specific abrasion state of the belt texture.

CONSTITUTION: An electric circuit 20 excited by a power generator 21 in a control unit 19 reaches an electric measuring instrument 22 which detects an electric resistance value R generated at the section part of the belt. This measuring instrument 22 is connected to a comparator 23, which compares a voltage detected by the measuring instrument, i.e., the resistance value R with the specific resistance value. This specific resistance value is supplied as an electric signal having the specific voltage value from a voltage generating device 24 to the comparator 23. Then when the resistance value R is equal to or larger than the specific resistance value, the comparator 23 operates an alarm means 25 to generate a signal, indicating that the belt will possibly be broken soon.