PROBLEM TO BE SOLVED: To provide a vaporizer, in which marks indicating replacement times are clearly visible, so that the replacement times are easily recognizable in accordance with the volume reduction state of volatile solid matter.SOLUTION: The vaporizer 1 includes the volatile solid matter 2 to reduce the volume as it gets in contact with air to vaporize volatile gas, and a holder 3 to hold the volatile solid matter 2. The holder 3 includes a circular part 31 to enclose the volatile solid matter 2, and a support part 33 projected from an inner circumferential surface of the circular part 31. The support part 33 is extended in a perpendicular direction to the inner circumferential surface of the circular part 31, and is embedded inside an outer circumferential part of the volatile solid matter 2. The volatile solid matter 2 is supported through the support part 33.
