To provide a resin composition low in dielectric constant and a photosensitive film using the same, high in pattern accuracy and in adhesion to the substrate, developable in water or in a dilute alkali solution, and suitable for the fabrication of solder resists and interlaminar insulation layers for printed wiring boards and IC packages.

The photosensitive resin composition is characterized in that it contains (A) a resin containing an unsaturated group prepared by the reaction of a (meth)acrylate, which is the product of reaction of (a) an epoxy resin having two or more epoxy groups in a molecule, (b) a compound having an unsaturated double bond and a carboxyl group in a molecule, (c) a saturated monocarboxylic acid which is optional, and (d) a polybasic acid anhydride as required, (B) a diluent, (C) a photopolymrization initiator, (D) a powder with its dielectric constant of 3.5 or less, and (E) a surfactant.