A method for making spectacle arms from composite material with differentiated rigidity, the arms defining a first portion and an adjacent second portion which is less rigid than the first portion. The method includes: providing a first layer of non-cross-linked fiber-reinforced polymer material in the first and second portions; providing a separating element in the first portion, and superimposing a second layer of non-cross-linked fiber-reinforced polymer material on the first layer so as to cover the separating element at the first portion and contact the first layer at the second portion; subjecting the first layer, the second layer, and the separating element interposed between them to a molding process at predetermined pressure and temperature levels so as to cross-link the polymer of the composite material, thus obtaining a thickness and rigidity of the arm at the first portion which are greater than the thickness and rigidity at the second portion.