In oder to prevent stone accidents, a mowing test was conducted to evaluate the performance of a reciprocating mower type bush cutter which were newly developed. This was compared with a rotating disc type.Some of our findings may be summarized as follows:1) With the reciprocating type cutter, most of the struck stones were not scattered. therefore the operator has no need to worry about mowing work.2) When the reciprocating type cutter struck against stones, the amount of GSR was much less than that obtained by using the rotating blade, which means that the mental stress of the operator was greatly reduced.3) The reciprocating type cutter has an disadvantage over the rotating type cutter in the amount of work done. It's work efficiency on level field and slope was about 80% of the rotating type cutter.4) The RMR for an operator on level field was 4.5 and 3.3 at a working width of 150cm respectively for the reciprocating type and the rotating type. The RMR on slope was 5.4 and 5.7 respectively for the reciprocating type and the rotating type.5) In mowing work using reciprocating type, grass was mown one way only. In addition, the bottom of the blade contacted with mown grass and trailed producing additional operating resistance.6) The optimum mowing width was considered to be 100cm from the results obtained in the test of surface EMG, RMR and work efficiency.