Embodiments include a blow molding machine, a method for replacing a blow mold unit, and a mold unit including a blow mold including first and second blow cavity split molds and a plurality of raised bottom molds; first and second pressure receiving plates; first and second fixing plates to which the first and second blow cavity split molds and the first and second pressure receiving plates are respectively fixed; a third fixing plate interposed between the first and second fixing plates and to which the raised bottom molds are fixed at a first surface thereof; a pressure receiving rod hanging down from a second surface and including an engaged portion engageable with the engaging portion; and a placement portion fixed to at least one of the first and second fixing plates and placing the third fixing plate thereon when the first and second blow cavity split molds are closed.