A stirring impeller to be attached to a stirring shaft provided in a stirring device, the stirring impeller comprising: a plate-shaped support part that is attached to the stirring shaft and formed in a circular shape; and a plurality of blade units that are disposed on an outer peripheral edge side of the support part and provided at predetermined intervals along a circumferential direction of the support part, wherein the support part includes a first surface and a second surface, wherein each of the blade units includes a first blade part that protrudes from one of the first surface and the second surface in the support part, a second blade part that protrudes from the other one of the first surface and the second surface in the support part and is made unsymmetrical to the first blade part, and an opening that is formed in at least one of the first blade part and the second blade part, characterized in that the opening is formed such that predetermined regions on a root side and a radial outer side of the first blade part or the second blade part are cut off in a linear shape or in a curved shape, and has a space through which an object to be stirred can pass, and in that the first blade part in one of two blade units adjacent to each other in the circumferential direction of the support part is provided on the first surface of the support part, the first blade part in the other one of the two blade units is provided on the second surface of the support part, the second blade part of the one blade unit is provided on the second surface of the support part, and the second blade part of the other blade unit is provided on the first surface of the support part. a plate-shaped support part that is attached to the stirring shaft and formed in a circular shape; and a plurality of blade units that are disposed on an outer peripheral edge side of the support part and provided at predetermined intervals along a circumferential direction of the support part, wherein the support part includes a first surface and a second surface, wherein each of the blade units includes a first blade part that protrudes from one of the first surface and the second surface in the support part, a second blade part that protrudes from the other one of the first surface and the second surface in the support part and is made unsymmetrical to the first blade part, and an opening that is formed in at least one of the first blade part and the second blade part, the opening is formed such that predetermined regions on a root side and a radial outer side of the first blade part or the second blade part are cut off in a linear shape or in a curved shape, and has a space through which an object to be stirred can pass, and in that the first blade part in one of two blade units adjacent to each other in the circumferential direction of the support part is provided on the first surface of the support part, the first blade part in the other one of the two blade units is provided on the second surface of the support part, the second blade part of the one blade unit is provided on the second surface of the support part, and the second blade part of the other blade unit is provided on the first surface of the support part.