Abstract: Seat plate (10) for supporting the pelvis of a person sitting in a seat (2), e.g. a seat in a vehicle. Known seat implementations only give limited support in a horizontal direction. This causes a noticeable problem in vehicle seats, since a person sitting on one is subjected to accelerations and retardations in both longitudinal and transverse directions. The muscles which are activated in such cases become tired relatively quickly, often resulting in that an incorrect sitting attitude is assumed which can give rise to skew loads as well as accelerating and amplifying the sense of tiredness and soreness. The invention relates to a seat plate (10) for positioning the pelvis of a sitting person so that no notable muscular work is required for maintaiing a correct sitting attitude. The seat plate (10) is thus formed with two raised, scythe-like ridges (11) each including a forward transverse ridge portion (13) and a longitudinal ridge portion (14) extending backwords from the transverse portion (13).