A support case for a turbomachine ring sector includes an annular body around a longitudinal axis of the case, and a downstream edge for attachment of the ring sector. The downstream edge extends from the body radially towards the inside of the case. The downstream edge extends circumferentially along a junction region between the body and a fixed vanes stage. The junction region includes a central portion and two lateral portions located on each side of the central portion, along a circumferential direction of the case with respect to its longitudinal axis. The central portion projects radially outwards from the case with respect to the lateral portions.