PURPOSE: To improve the balance of characteristics between exposed parts and unexposed parts by incorporating a polymer having specific side chains and a compd. which generates an acid when irradiated with photoirradiations or ionizing radiations as essential components into the above pattern forming material.

CONSTITUTION: The polymer having the side chains contg. a tert- amyloxycarbonyl group and the compd. which generates the acid when irradiated with photoirradiations or the ionizing radiations are used as the essential components. The acid is generated in the irradiated parts (exposed parts) when light or the ionizing radiations are radiated to such pattern forming material. The tert-amyloxycarbonyl group is desorbed by this acid and the groups (-OH groups, etc.) having polarity are formed. Then, a large difference appears in the solubility characteristics between the exposed parts and the unexposed parts and, therefore, whether the exposed polymer or the unexposed polymer is removed is easily determined according to purposes by properly selecting a developer. The formation of patterns with a high contrast is possible.