In a liquid substance supply device, a three port two valve directional control valve is provided in a transfer line, and a substance container and the transfer line are connected together by a four port three valve directional control valve in such a way that the four port three valve directional control valve and the substance container can be removed from the transfer line as a unit. Furthermore, in a vaporizer, an orifice member is provided to surround the end portion of an internal conduit in which flows a mixture substance consisting of a gas and a liquid substance mixed therewith, and gas for atomization is spouted into a vaporization chamber through a gap defined between the internal conduit and the orifice member. Yet further, the temperature of a vaporization surface in the vaporization chamber can be controlled independently in correspondence with the nature of the liquid substance.