A grass cutter blade of the present invention is for use in a grass cutter. The grass cutter blade inclines: a connection part for connection to the grass cutter and a peripheral part extending from the connection part as a center and having an outer periphery that is inclined downwardly. The peripheral part is provided with a plurality of cutouts, each of which has an opening at the outer periphery. The peripheral part includes a region located further away from a rotation axis of the grass cutter blade than an edge portion of each of the plurality of cutouts. There exist, in the edge portion, a first end section and a second end section which extend to a deepest section having a deepest depth in a direction toward a center of the grass cutter blade from the outer periphery of the peripheral part, the first end section and the second end section pass through respective regions during rotation of the grass cutter blade, and a distance exists between the respective regions in a direction orthogonal to the rotation axis with respect to a predetermined range in an up-and-down direction.