An epoxy resin composition can be used for forming a film having excellent water-repellency on a substrate surface. The epoxy resin composition contains (a) an epoxy resin having at least two alicyclic epoxy groups, at least one perfluoroalkyl group having 6 to 12 carbon atoms, and at least one alkylsiloxane group and (b) a cationic polymerization catalyst. The alicyclic epoxy groups and the perfluoroalkyl group are present in branched chains of the epoxy resin, and the alkylsiloxane group is present in the main chain of the epoxy resin.