A cutting head for an edge trimmer, comprising: a lower shell and an upper shell, at least one of which is associable with the drive shaft of a hedge trimmer to be operated in rotation around a rotation axis; two or more coupling pins, associated with the shells (2,3) and set up to enable respective cutting elements (B,W) to be coupled; wherein the shells (2,3) are slidable in relation to one another along the rotation axis between an operating position, in which they are alongside one another, and a change position, in which they are at least partially separated from one another; wherein the coupling pins, in the change position, have a free end that is accessible to enable a cutting element (B,W) to be inserted or extracted; an elastic pusher that is set up for pushing the lower shell and the upper shell to the operating position; characterised in that: the lower shell is provided with an axial body, which is concentric to the rotation axis, set up for being inserted through a prismatic coupling into a seat of the upper shell, concentrically to the rotation axis; the shells (2,3) are guided in sliding by the prismatic coupling between the axial body and the seat, such that the axial body can slide within the seat, without rotating with respect to the latter, along the rotation axis; in any position between the operating position and the change position, the shells (2,3) are always integral with one another with respect to the rotation around the rotation axis. a lower shell and an upper shell, at least one of which is associable with the drive shaft of a hedge trimmer to be operated in rotation around a rotation axis; two or more coupling pins, associated with the shells (2,3) and set up to enable respective cutting elements (B,W) to be coupled; wherein the shells (2,3) are slidable in relation to one another along the rotation axis between an operating position, in which they are alongside one another, and a change position, in which they are at least partially separated from one another; wherein the coupling pins, in the change position, have a free end that is accessible to enable a cutting element (B,W) to be inserted or extracted; an elastic pusher that is set up for pushing the lower shell and the upper shell to the operating position; characterised in that: the lower shell is provided with an axial body, which is concentric to the rotation axis, set up for being inserted through a prismatic coupling into a seat of the upper shell, concentrically to the rotation axis; the shells (2,3) are guided in sliding by the prismatic coupling between the axial body and the seat, such that the axial body can slide within the seat, without rotating with respect to the latter, along the rotation axis; in any position between the operating position and the change position, the shells (2,3) are always integral with one another with respect to the rotation around the rotation axis. the lower shell is provided with an axial body, which is concentric to the rotation axis, set up for being inserted through a prismatic coupling into a seat of the upper shell, concentrically to the rotation axis; the shells (2,3) are guided in sliding by the prismatic coupling between the axial body and the seat, such that the axial body can slide within the seat, without rotating with respect to the latter, along the rotation axis; in any position between the operating position and the change position, the shells (2,3) are always integral with one another with respect to the rotation around the rotation axis.