The present invention provides a non-woven fabric for supporting a solid electrolyte in which heat-fusible composite fibers with a crimp are contained in an amount of not less than 60 mass % and not more than 100 mass % and are heat-fused, and a solid electrolyte sheet. The non-woven fabric for supporting a solid electrolyte is excellent in process performance, is satisfactorily filled with a solid electrolyte, is suitable for achieving a thin solid electrolyte sheet, and has few hole defects. The solid electrolyte sheet is excellent in self-sustainability and flexibility.