The breaking of a small stone sample (tuff) caused by freeze-thaw cycles was detected by sing-around measurement of ultrasonic sound. The measurement system was automatically controlled by a computer. The velocity of ultrasonic sound (Vp) through the stone sample and the temperature of the sample (t) were recorded by a printer and stored in a floppy disk. When a freeze-thaw cycle was completed, a graph showing the relation between Vp and t was drawn by a plotter. The effectiveness of silcone resin was verified by measuring Vp changes of samples. Vp of a treated sample did not change significantly after 5 cycles of freeze-thaw, while that of an untreated sample largely decreased and some were broken into two pieces. The main advantages and disadvantages of the sing-around measurement are also discussed.