Abstract: A pressure regulator and a method for regulating the same is for predicting occurrence of dew condensation inside components of a vehicle so that the cause of the occurrence of dew condensation is removed in advance before occurrence of dew condensation. The pressure regulator includes a case in which an opening is provided at one end of the case, an outlet is provided at the other end of the case, and the opening is provided to be inserted into a housing of the component, a fan provided inside the case and a filter provided inside the case, the filter allowing gas to be discharged from the inside of the component to the outside of the component while blocking inflow of moisture from the outside of the component to the inside of the component.