PROBLEM TO BE SOLVED: To efficiently volatilize a volatilization agent.SOLUTION: A volatilization device 10 comprises: a bottom-closed cylindrical housing body 12 which is arranged at the front of a ventilation port A and penetrated by an introduction port in a rear surface part 22a covering the ventilation port A in a peripheral wall 22 a discharge container 13 which is accommodated in the housing body 12 and discharges a volatilization agent stored therein toward the rear surface part 22a side a lid member 14 which is mounted to an opening end part of the housing body 12 so as to be rotatable around an axis O of the housing body 12 and an impregnation body 15 which is arranged between the rear surface part 22a and the discharge container 13 to cover the introduction port. A part avoiding the rear surface part 22a in the peripheral wall part 22 is penetrated by a lead-out port. The lid member 14 is provided with an engaging part 37 which is engaged with the impregnation body 15 and moves the impregnation body 15 around the axis O in accordance with rotation of the lid member 14.
