To provide a solid electrolyte simply manufacturable in a short time, causing little leakage of an electrolyte and having excellent conductivity.

In this solid electrolyte, an electrolyte (ii) is carried in a three dimensional cross-linking structure (i) obtained when a reactive functional group contained compound (a) reacts with a compound (b) having a functional group capable of reacting with the reactive functional group which is a component of the compound (a).