A swing prism for an endoscope with a variable viewing direction, the swing prism including: a flat light inlet surface, a flat light outlet surface, and a flat mirror surface, wherein the flat light inlet surface and the flat light outlet surface are arranged at a 90° angle relative to each other and are each arranged at a 45° angle relative to the flat mirror surface, the swing prism is configured as a cylinder-section-shaped body with a base surface configured as a circle segment, and a cylindrical axis of the cylinder-section-shaped body is perpendicular to the flat light outlet surface, and in a projection onto the flat light outlet surface, the flat light inlet surface constitutes a chord which delimits the circle segment.
