Fresh air device and air conditioner

The utility model discloses a fresh air device and an air conditioner. The fresh air device comprises a shell, the shell is provided with a first cavity and a second cavity, and the shell is provided with a first air opening, a second air opening and a third air opening capable of being opened and closed; the first plugging assembly is rotatably arranged in the first cavity and can be switched between a first position and a second position; the fan assembly is arranged in the second cavity, the fan assembly is provided with an air outlet and an air inlet, when the first blocking assembly is located at the first position, the first blocking assembly divides the first cavity into a first air duct and a second air duct, the second air opening and the third air opening which can be opened and closed are in an open state, and the first air duct communicates with the first air opening and the air inlet; the second air duct communicates with the air outlet and the second air port; and the filtering assembly is arran