A uniform gel electrolyte having high durability and use thereof, in particular, batteries or capacitors using such a gel electrolyte. The gel electrolyte includes a gel composition containing an electrolyte salt, a solvent for the electrolyte salt, and a polymer matrix, wherein the polymer matrix comprises a crosslinked polymer prepared by polymerizing a bifunctional (meth)acrylate represented by the following formula (I): ##STR00001## wherein R represents a divalent organic group, and R.sub.1 represents a hydrogen atom or a methyl group.