a plug part attachable to and detachable from an accessory socket provided in a cabin;

a steam fog generator body extending from said plug part into the cabin, power being supplied from the vehicle through said plug part;

said steam fog generator body including a holding part for attachably and detachably holding a cartridge containing liquid chemicals, a heating element that produces heat by the power supplied through said plug part to heat said liquid chemicals in a container part of said cartridge and allows said liquid chemicals to pass outward through a permeable membrane covering a top opening of said container part, and divergence means for diverging said liquid chemicals having passed through said permeable membrane into the cabin;

said steam fog generator body including an operating switch for turning on and off the power to be supplied to said heating element;

said holding part including a loading/unloading port for loading and unloading said cartridge into and from said steam fog generator body, and a storage space for loadably and unloadably storing said cartridge inserted through said loading/unloading port;

said divergence means being constituted by a divergence port that provides communication between said storage space and the outside;

at least one of said container part and said permeable membrane of said cartridge, and said steam fog generator body being made of a transparent material;

said steam fog generator body including an observation part for observing the amount of liquid remaining in said cartridge; and

said steam fog generator body extending from said plug part being foldably connected to said plug part, and limiting means being provided for limiting a folding direction of said steam fog generator body to a bottom side of said held cartridge.