To simply remove a cutting blade from the moving surface of a straw mat bed when the straw mat bed is rotated and moved within a horizontal plane by forming a blade for cutting the straw mat bed by cutting off one side from the vicinity of the shaft support hole to be substantially semicircular, and taking the outer periphery of the semicircular part as a cutting edge part.

A straw mat bed cutting blade 1 is formed substantially semicircular by cutting off one side from the vicinity of a shaft support hole 2, and the outer periphery of the semicircular part is taken as a cutting edge part 3. The straw mat bed cutting blade 1 is rotatably supported by a support shaft in use, and the straw mat bed cutting blade 1 is turned in the direction of cutting the straw mat bed to cut the bed by the cutting edge part 3 of the outer periphery of the semicircle. After the end of cutting, the cutting edge part 3 is put upward without directing to the straw mat bed. Thus, the cutting edge part 3 is not directed to the straw mat bed, but stopped upward in the state of not interfering with the straw mat bed during non-operation for the straw mat bed, whereby in rotating and moving within a horizontal plane of the straw mat bed, the straw mat bed cutting blade 1 can be simply removed from the moving plane of the straw mat bed.