The subject of the present invention is to provide a positive photosensitive resin composition which is excellent in adhesion and patterning property and capable of giving a cured product with good elongation. To solve the problem, a positive photosensitive resin composition is provided, which comprises (A) a polybenzoxazole precursor, (B) a photoacid generator, (C) a silane coupling agent containing nitrogen atom, and (D) an adhesion enhancer with an amine value of 20 mgKOH/g or more and 100 mgKOH/g or less. The positive photosensitive resin composition further comprises (E) a crosslinking agent, which is an agent capable of being crosslinked or polymerized by heating. The crosslinking agent is crosslinked by reacting with polybenzoxazole precursor or polybenzoxazole in a thermal treatment step after coating, exposure and development. The polymerization of the crosslinking agent can increase the residual film rate in the unexposed area, prevent the exposed area from remaining, and improve the patterning property. Based on (A) as 100 parts by mass, (B) is 0.5 to 40 parts by mass, (C) is 0.1 to 10 parts by mass, and (D) is 0.1 to 10 parts by mass. The mass ratio of (C) to (D) (mass of (C): mass of (D)) is 1:0.2 to 1:10. The silane coupling agent containing nitrogen atom may be amino-containing alkoxysilane. In addition, the present invention further provides a dry film with a resin layer, wherein the resin layer is obtained by coating the positive photosensitive resin composition on the film and drying it. Furthermore, the present invention provides a cured product obtained by curing the positive photosensitive resin composition or the resin layer of the dry film. According to the present invention, the method for manufacturing the positive photosensitive resin composition comprises the steps of adding (C) while stirring (A) and (B) in a solvent, and then adding (D).