To provide a grinding apparatus that enables all the abrasive grains to be reliably collected on the peripheral surface side of a bladed wheel, and also recovered without injection in a useless direction, thereby achieving intense injection from a nozzle.

The grinding apparatus includes: a sealable operation chamber; a hopper continuously arranged in the lower part of the chamber: and an injection apparatus supplied with abrasive grains through a fall cylinder from the hopper, and injecting the abrasive grains into the inside of the operation chamber through the nozzle. The injection apparatus is constituted such that the bladed wheel has two disks sandwiching a plurality of blades, a belt is wound around the bladed wheel so that part of peripheral surface of the bladed wheel is opened, and the front side disk has a throw-in opening of the abrasive grains facing the fall cylinder. The blades are formed into a wedge shape which becomes thicker as they go further from the central side of the bladed wheel to the peripheral surface side. Flange plates are integrally formed in the perpendicular direction to both side surfaces where the blades are brought into contact with the two disks, respectively, and a material to constitute the blades is constituted of a material having a higher abrasion resistance than a material constituting the disks.