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 A and has a back wall part provided with a vent hole 33, a discharge container 12 which is arranged on the side opposite to the vent duct A, with the back wall part between the vent duct A and the discharge container 12, and supported by the support member 11 and discharges a volatile agent contained in it, an impregnation body which is impregnated with the volatile agent discharged from the discharge container 12 and blown with air from the vent duct A through the vent hole 33 and an attachment member 15 which is provided in the back wall part and is to be attached to the vent duct A. In the attachment member 15, there are provided a base part 51 arranged in the back wall part and a plurality of clip parts 52 which are arranged in the base part 51 and engaged each in to-be-engaged parts A1 provided in the vent duct A. At least one of the clip parts 52 is a movable clip part 52b arranged movably in the base part 51.
