STRAIN MEASURING DEVICE

PROBLEM TO BE SOLVED: To provide a strain measuring device that reduces thermal fluctuation of air occurring in the vicinity of the surface of a high-temperature measurement object and improving accuracy of an image obtained by photographing with an imaging device so as to improve measurement accuracy of strain occurring due to image processing.SOLUTION: A strain measuring device comprises: an imaging device 12 that obtains an image by photographing the surface of a high-temperature measurement object 14; fluctuation reduction means 11a for reducing thermal fluctuation of air occurring in the vicinity of the surface of the measurement object; and an arithmetic device 13 that performs arithmetic processing on the obtained image to calculate strain on the surface of the measurement object. The fluctuation reduction means 11a comprises: a heat insulating body 21 that forms a space inside thereof to cover a periphery of an area where strain of the high-temperature measurement object 14 is measured; and a light transmission member 22 having light transmissivity that is provided on a side surface being an imaging device 12 side of the heat insulating body 21.