A seat for amusement apparatus, unusually suitable for allowing the user to adopt a new position on the apparatus, comprising a support and means for immobilising the user on the support. The immobilising means comprise at least one support in front of the user and opposing means suitable for acting on the user's back. The opposing means comprises an arm which can move between a lowered position in which the user can sit down on the support and a raised position in which one end of the arm abuts against the user's back.