Abstract: An evaporation loss control device provided with a polymer chamber filled with polymer absorbent, a charcoal chamber filled with charcoal, introduction and purging pipes for connecting the polymer chamber with a fuel tank and an engine intake passage, respectively, an air pipe for ventilation connected to the charcoal chamber, and a vapor passage, which has various forms. For example, the vapor passage may be formed in spiral to encircle the polymer chamber, or provided between the polymer and charcoal chambers, thus allowing the evaporated fuel to pass therethrough. The vapor passage is constructed to prevent the evaporated fuel trapped by the polymer absorbent from flowing into the charcoal chamber, and also to prevent the liquid fuel from being absorbed by the charcoal.