A cutter blade (26) for a mower is driven to rotate about a vertical axis (26a) inside a housing (21). The cutter blade (26) includes a blade body (70), a blade portion (81) formed in the blade body (70) and a wind generating portion (82) formed in the blade body (70) on its side opposite in a width direction thereof to the side where the blade portion (81) is formed, the wind generating portion (82) being formed by being raised and bent from the blade body (70) over a predetermined area from an end in a longitudinal direction thereof. At an outer end portion of the wind generating portion (82a) in the longitudinal direction of the blade body, there is formed at least one recessed portion (90) recessed more inwards than the remaining portion of the outer end portion (82a).
