A humidity regulating apparatus, which is applied in a target environment where the relative humidity is to be regulated, comprising: a hygroscopic wheel for being rotated in a direction to absorb moisture and water surrounding the hygroscopic wheel; a wetting means disposed in a position corresponding to the hygroscopic wheel, wherein the wetting means performs a movement in relation to the hygroscopic wheel and is controlled to supply moisture or water to the hygroscopic wheel; a heating means thermally connected with the hygroscopic wheel, wherein the heating means performs a movement in relation to the hygroscopic wheel to heat the moisture and water absorbed within the hygroscopic wheel to evaporate into vapor; characterized by: a transporting means having a vapor inlet opening, a humidifying outlet opening, and a dehumidifying outlet opening, wherein the vapor inlet opening is connected with the heating means for importing the vapor thereto, the transporting means is configured to switch between a state that the vapor inlet opening interconnects with the humidifying outlet opening with which the target environment is interconnected and a state that the vapor inlet opening interconnects with the dehumidifying outlet opening; and a condensing means, connected with the dehumidifying outlet opening, for collecting and condensing the imported vapor to reduce the relative humidity in the target environment. a hygroscopic wheel for being rotated in a direction to absorb moisture and water surrounding the hygroscopic wheel; a wetting means disposed in a position corresponding to the hygroscopic wheel, wherein the wetting means performs a movement in relation to the hygroscopic wheel and is controlled to supply moisture or water to the hygroscopic wheel; a heating means thermally connected with the hygroscopic wheel, wherein the heating means performs a movement in relation to the hygroscopic wheel to heat the moisture and water absorbed within the hygroscopic wheel to evaporate into vapor; characterized by: a transporting means having a vapor inlet opening, a humidifying outlet opening, and a dehumidifying outlet opening, wherein the vapor inlet opening is connected with the heating means for importing the vapor thereto, the transporting means is configured to switch between a state that the vapor inlet opening interconnects with the humidifying outlet opening with which the target environment is interconnected and a state that the vapor inlet opening interconnects with the dehumidifying outlet opening; and a condensing means, connected with the dehumidifying outlet opening, for collecting and condensing the imported vapor to reduce the relative humidity in the target environment. a transporting means having a vapor inlet opening, a humidifying outlet opening, and a dehumidifying outlet opening, wherein the vapor inlet opening is connected with the heating means for importing the vapor thereto, the transporting means is configured to switch between a state that the vapor inlet opening interconnects with the humidifying outlet opening with which the target environment is interconnected and a state that the vapor inlet opening interconnects with the dehumidifying outlet opening; and a condensing means, connected with the dehumidifying outlet opening, for collecting and condensing the imported vapor to reduce the relative humidity in the target environment.