A medical capsule housing includes first and second outer members made of a resin material, both having an opening at one end. The first and second outer members are thermally welded by ultrasonic welding at an abutting portion. The abutting portion includes a sharp edged line portion which forms the opening end portion of the first outer member and an inclined surface portion which forms the opening end portion of the second outer member. The sharp edged line portion is provided in a closed space formed by the first outer member and the second outer member before the ultrasonic welding.