[Problem] To provide a rotating blade for a grass trimmer configured in such a manner as to allow the extension length of a cord-shaped cutting member to be adjusted simply, and also to allow the cord-shaped cutting member to be replaced simply. [Solution] The rotating blade A for a grass trimmer comprises a holding member 100 that is attached to a rotating blade attachment axis 14 of the grass trimmer B and is made to rotate, and a holding mechanism 200 holding the cord-shaped cutting member 40 in such a manner that the proximal end side thereof is held by the holding member 100 and the distal end side thereof extends outward in the radial direction of the holding member. The holding mechanism 200 comprises a coupling part 210 whereto one end of the cord-shaped cutting member 40 is connected, a plurality of wrapping parts 220a, 220b, 220c, 220d arranged in the circumferential direction of the holding member 100, wherearound the cord-shaped cutting member 40 is wrapped, and a mounting facilitation means 300 facilitating the mounting of the cord-shaped cutting member 40. The mounting facilitation means 300 is formed from a groove section 122 opening outward in the radial direction of the holding member 100 and includes a straight line L which joins, from among the plurality of wrapping parts 220a, 220b, 220c, 220d, the back position of the wrap part 220a closest to the coupling part 210 to the back position of the wrap part 220d most distant from the coupling part 210.Le problème décrit par la présente invention est de fournir une lame rotative pour une tondeuse à gazon conçue de manière à permettre à la longueur d'extension d'un élément de coupe en forme de cordon d'être ajustée de manière simple, et également de permettre à l'élément de coupe en forme de cordon d'être remplacé de manière simple. La solution selon l'invention porte sur une lame rotative A pour une tondeuse à gazon comprenant un élément de maintien 100 qui est fixé à un axe de fixation de lame rotati
