A solid electrolyte having an aromatic ring, wherein a sulfonic acid group represented by the following formula (1) bonds to the aromatic ring. wherein B1 and B2 each independently represents a linking group, at least one of B1 and B2 is a fluorinated alkylene group, X represents a group containing a hetero atom, M represents a cation, m1 represents an integer of 1 or more, m2 represents 0 or 1 and n1 represents an integer of 1 to 20.The solid electrolyte exhibits a high ion conductivity.