A wheelchair occupant restraint device includes: a wheelchair retractor which is disposed in a vehicle cabin, and around which one end portion of a wheelchair belt member is wound; a wheelchair buckle which is disposed on the opposite side of a securing space for a wheelchair from the wheelchair retractor, and on which a wheelchair tongue plate attached to the other end portion of the wheelchair belt member is able to be mounted; an occupant retractor which is disposed on the opposite side of the securing space from the wheelchair retractor, and around which one end portion of an occupant belt member is wound; and an occupant buckle which is disposed on the opposite side of the securing space from the occupant retractor, and on which an occupant tongue plate attached to the other end portion of the occupant belt member is able to be mounted.