[Object] The invention provides a mount/dismount structure of a mowing blade of a mowing machine that achieves simple and secure fitting of the mowing blade fitted to a front end of a stay, without requiring a particular tool.[Solving means] The invention is a mount/dismount structure of a mowing blade that is fitted to a front end of a rotary stay of a crass mower. A fitting trench 6 of a mowing blade 5 is formed on a head portion of a stay 1. The mowing blade 5 is rotatably fitted to the fitting trench 6 via a locking portion 10. The fitting trench 6 has a mount/dismount portion 7 of the locking portion 10, and a fixing portion 9 of the locking portion 10. The locking portion 10 is inserted from the mount/dismount portion 7, and the mowing blade 5 is fitted by sliding the locking portion 10 to the fixing portion 9 along the fitting trench 6. The mount/dismount portion 7 is set at a base side of the stay, and the fixing portion 9 is set at a front end side of the stay.
