PROBLEM TO BE SOLVED: To volatilize a volatile agent efficiently.SOLUTION: A volatilization device 10 includes a support member 11 which is arranged in front of a vent duct and has a back wall part 21 provided with a vent hole 33, a discharge container 12 which is arranged on the side opposite to the vent duct, with the back wall part 21 between the vent duct and the discharge container 12, and supported by the support member 11 and discharges a volatile agent contained in it and an impregnation body 13 which is impregnated with the volatile agent discharged from the discharge container 12 and blown with air from the vent duct through the vent hole 33. The discharge container 12 has a head part 38b provided with a discharge hole 40 which discharges the volatile agent outward in the radial direction of the discharge container 12, and the impregnation body 13 has such a cylindrical shape as to surround the head part 38b from the outer side in the radial direction.