To provide a work processing apparatus equipped with a vaporizer that requires no carrier gas and can vaporize a vaporization target liquid having a relatively high flow rate, and a method for manufacturing a processed work. A vaporizer 1 includes a vaporization part 10 including a heat storage body 11 having a heat capacity higher than that of a vaporization target liquid Fq by a predetermined ratio, and a heat supplier 20 for supplying heat to the vaporization part 10. The predetermined ratio is a ratio of heat capacity at which a temperature drop of the heat storage body 11 by heat transfer from the heat storage body 11 to the liquid Fq flowing through a path 12 is within a predetermined range, wherein the amount of heat transferred from the heat storage body 11 to the liquid Fq is an amount of heat necessary to vaporize the liquid Fq at a planned proportion. A work processing apparatus 100 includes the vaporizer 1, a chamber 5, and a vacuum pump 6 for creating a negative pressure in the chamber 5. The method of manufacturing a processed work includes taking the work W into the chamber 5, supplying a processing gas Fg generated in the vaporizer 1 into the chamber 5, and performing predetermined processing on the work W under an atmosphere of the processing gas Fg in the chamber 5.