PURPOSE: To provide a positive type photoresist material which has a long-term preservation life without requiring a thermal post treatment, affords a relief structure of good resolution and has high photosensitivity.

CONSTITUTION: This positive type photoresist compsn. consists of at least one kind of hompolymers or copolymers contg. acid active (acidlabile) α-alkoxyalkyl ester group, at least one kind of carboxyl-contg. copolymers having 0.40 to 5.50mol/kg content of carboxyl groups, at least one kind of compds. forming an acid in exposure to chemical rays and is developable with an aq. alkaline medium consisting of an org. solvent. This process for production of the relief structure uses such photoresist compsn.