A photoresist composition comprising: a resin soluble in an aqueous alkaline solution, having units of an aliphatic cyclic hydrocarbon main frame and units derived from maleic anhydride and/or units derived from a maleimide; and a photosensitive agent in a sufficient amount to promote or hinder the solubility of said resin in an aqueous alkaline solution upon exposure to active radiation so as to create a substantial difference in the solubility as between an exposed portion and a non-exposed portion and to form a positive or negative image by subsequent development with an aqueous alkaline solution.
