Fan filtering device and ventilation device

The utility model provides a fan filtering device and a ventilation device, and belongs to the technical field of ventilation. The fan filtering device comprises a supporting frame, a winding roller, an unwinding roller and a filtering coiled material, the supporting frame is provided with a filtering opening for air circulation, the winding roller and the unwinding roller are rotatably installed on the supporting frame, and the winding roller and the unwinding roller are parallel to each other and arranged at intervals; the filtering coiled material comprises a winding section wound on the surface of the winding roller, an unwinding section wound on the surface of the unwinding roller and a middle section located between the winding section and the unwinding section in the length direction, and at least part of the middle section covers the filtering opening. According to the draught fan filtering device, the winding roller and the unwinding roller are matched to switch the filtering coiled materials located