A humeral prosthesis, for the articulation of a humerus in a scapula of a shoulder having a glenoid cavity, includes an articulation device able to be associated both with an articulation element mounted on the glenoid cavity, and also at the top of said humerus by an attachment element. The articulation device comprises a first element able to articulate with the articulation element and a second element associated with the attachment element, the first element and the second element being pivoted to each other around a pivoting axis to allow a free relative rotation thereof around the pivoting axis.