To obtain a mixture having good process properties by blending a polymer-like binder containing N-(4-sulfamylphenyl)maleimide units and a radiosensitive compound.

This is a radiosensitive mixture containing 10-95 wt.% of a binder which is a polymer having a weight average molecular weight of 1,000-100,000 containing 10-90 mol.% of N-substituted maleimide units of formula I which binder is insoluble to water but is soluble to or swelling alkaline aqueous solution, and 3-50 wt.% of a 1,2-quinonediazide compound for a positive type or a diazonium compound for a negative type. The monomer of formula II is obtained by reacting 4-aminobenzenesulfonamide and maleic anhydride in N-diethylacetamide to obtain maleimide acid and converting it to an N- substituted maleimide derivative in a mixture of acetic anhydride and sodium acetate. In the formulas, R1 to R4 are each H, a halogen, hydroxyl or the like; and R5 is H, an alkyl, an alkanoyl or the like.