An intravaginal support device is disclosed, which is capable of being expanded and contracted in a state of being inserted in a vagina for treating pelvic organ prolapse. The intravaginal support device can include an opening/closing portion capable of switching operations between an open state for allowing passage of fluid therethrough and a cut-off state for cutting off passage of the fluid, a bag portion being expandable by flowing-in of fluid through the opening/closing portion and being contractible by flowing-out of the fluid through the opening/closing portion, and an insertion guide portion adapted to guide the bag portion into the vagina, the insertion guide portion extending along at least part of an outer surface of the bag portion from a vaginal orifice side end portion of the bag portion to a vaginal depth side end portion of the bag portion.
