PROBLEM TO BE SOLVED: To provide an acid proliferation agent sealed micro capsule which is suitably used for curing of an epoxy resin and the like as a curing agent excellent in storage stability and curing characteristics; a method for producing the acid proliferation agent sealed micro capsule; and a photosensitive epoxy resin composition containing the acid proliferation agent sealed micro capsule.SOLUTION: In an acid proliferation agent sealed micro capsule, an acid proliferation agent having a group causing an acid proliferation reaction is sealed in a shell, as a core.