Abstract: The invention relates to an armrest (1) for a motor vehicle seat (8) with seatback (R), which pivots downwards with its end designed as a disk (1a) about a bearing journal (3) in a housing (2) after the release of a locking device (4), into a release position, and by being raised again is capable of pivoting towards the seatback (R) into its locked position of use. The present invention creates an armrest (1) of this nature, which, with problem-free low-friction switching, and with simple structural means, guarantees a secure position of use, optionally with or without overload protection. To that end, the locking device (4) includes of a setting piston (7), capable of movement approximately radially to the bearing journal (3), and a locking slide (9) capable of displacement therein, in a transverse aperture (7a). The setting piston (7) features an engagement projection which interacts with an engagement recess (11).