A photosensitive epoxy resin composition for formation of an optical waveguide is provided, which contains an epoxy resin component and a photo-cationic polymerization initiator, wherein the epoxy resin component includes: (a) a solid bisphenol-A epoxy resin having a softening point of not higher than 105° C.; (b) a solid polyfunctional aliphatic epoxy resin having a softening point of not higher than 105° C.; and (c) a liquid long-chain bifunctional semi-aliphatic epoxy resin, wherein the epoxy resin (a) is present in a proportion of 60 to 70 wt. % based on the weight of the epoxy resin component, wherein the epoxy resin (b) is present in a proportion of 20 to 35 wt. % based on the weight of the epoxy resin component, wherein the epoxy resin (c) is present in a proportion of 5 to 10 wt. % based on the weight of the epoxy resin component.