PROBLEM TO BE SOLVED: To simply and easily assemble a structure by pivotally supporting a vertical cutting blade of a cutting blade body 3 by upper and lower coaxial opposing headed pins.SOLUTION: A cutting blade body 3 is provided under a vertical cutting blade shaft 4 to be driven by a motor M, and cutting blades 31 are swingably provided at a plurality of places at intervals in the circumferential direction in a support body 3B of the cutting blade body 3 via cutting blade pins 30. A pair of vertical cutting blades 31U and 31D is disposed at each place. Each cutting blade pin 30 is formed of a pair of headed pins 30U and 30D which are opposed to each other from above and below and which coaxially penetrate the support body 3B and the vertical cutting blades 31. Distal ends of the headed pins 30U and 30D are formed in half shapes in the circumferential direction to be engaged with each other from above and below, and a stopper 32 is inserted into the engaged half shaped portions 30u and 30d.
