PURPOSE: To obtain a tension measuring device by which the operating efficiency of the inspection of a driving belt such as a V-belt or the like is enhanced by a method wherein a hook which has been hung on the belt is pulled up so as to measure a tension, a danger that the measuring device is detached from the belt is prevented and the loosened size of the belt is measured simultaneously together with the tension.

CONSTITUTION: A tension measuring device is provided with a hook 4, for tension measurement, which is installed at the tip of a wire 2 for tension measurement and which is hung on the upper side of a V-belt 10 as an object to be measured, with a hook 5, for size measurement, which is installed at the tip of a wire 3 for loosened-size measurement and which is hung on the lower side of the V-belt 10 as the object to be measured and with a tension-measuring- device body 1 which comprises a tension display part 6 and a loosened-size display part 7 integrally. When the tension-measuring-device body 1 is pulled up by a grip 9, a tension which has been applied to the wire 2 for tension measurement is displayed on the tension display part 6, and the pulled-up amount of the tension-measuring-device body 1, i.e., the loosened size of the V-belt 10, is displayed on the loosened-size display part 7.