A vaporizer, capable of stabilizing the behavior of pressure inside the vaporizer, includes a chamber having an inlet and an outlet, a heating device that heats the inside of the chamber, a partition wall structure 13 that is provided inside the vaporizer and partitions the liquid material inside the chamber into a plurality of sections, and liquid distribution portions 20 that are provided at the lower portion of the partition wall structure 13 and that allow liquid distribution among the sections partitioned by the partition wall structure 13, and the partition wall structure includes a grid-like, honeycomb-shaped, mesh-like, or pipe-shaped partition wall.