Abstract: A positive photosensitive composition comprising (A) a compound which generates an acid upon irradiation, and (B-1) a resin having a group which is decomposed by acid to increase solubility in an alkaline developing solution containing at least one structure represented by formulae (I), (II) and (III) or (B-2) a resin having at least one monovalent polyalicyclic group represented by formula (Ib) and a group which is decomposed by an acid to increase solubility in an alkaline developing solution. The positive photosensitive composition has high transmittance to ultraviolet light having a wavelength of 220 nm or less and exhibits good dry etching resistance. Further, the positive photosensitive composition exhibits high sensitivity, good resolution, and good pattern profile when ultraviolet light having a wavelength of 250 nm or less is employed as an exposure light source.