Simplification and downsizing of the structure of an evaporation supply apparatus for the raw material used in manufacturing a semiconductor by the MODVC method are implemented. At the same time, stabilization and improvement of the quality of the semiconductor are implemented by highly accurately controlling the amount of raw material supplied to the process chamber. The evaporation supply apparatus of the present invention includes: a source tank in which a raw material is pooled; a flow rate control device that, while regulating the flow rate of carrier gas at a constant flow rate from a carrier gas supply source, supplies the carrier gas into the raw material in the source tank; a primary piping path for feeding mixed gas G 0 , made up of raw material vapor G 4 and carrier gas G 1 , pooled in an upper space of the source tank; an automatic pressure regulating device that regulates the opening degree of a control valve, interposed in the tail end of the primary piping path, based on the detected values of the pressure and temperature of mixed gas G 0 in the primary piping path to regulate the cross-sectional area of the passage through which the mixed gas G 0 is distributed so as to hold a pressure of the mixed gas G 0 inside the source tank at a constant value; and a constant-temperature heating unit for heating the source tank and parts excluding an arithmetic control unit of the automatic pressure regulating device to a set temperature, in which the mixed gas G 0 is supplied to a process chamber while controlling the pressure inside the source tank to a desired pressure.