To provide a cosmetic and/or dermatologic composition in a water- in-oil type emulsion form making it possible to obtain a water-in-oil type emulsion capable of containing a large amount of a hydrocarbon-based oil without flocculating.

This cosmetic and/or dermatologic composition in the water- in-oil type emulsion form is characterized by containing at least one amphoteric 2-acrylamido-2-methylpropanesulfonic acid polymer or copolymer having a hydrophobic graft selected from an oxyalkylene hydrocarbon base group containing a 6 to 30C hydrocarbon base group, an oxyalkylene hydrocarbon base group containing a 6 to 30C hydrocarbon base group and at least one oxyalkylene unit, a perfluoroalkyl group, a silicon group and their mixtures, wherein the hydrophobic graft molar rate of the polymer or copolymer is at least 50%.