To provide a polyelectrolyte having an excellent ionic conductance characteristic because a conventional polyelectrolyte has a problem that an extraction current is small because of having low ionic conductance, and has a limitation in use at low temperature because its ionic conductance is generally extremely dropped when the temperature drops below 0°C.

This polyelectrolyte is characterized by comprising a polymer compound A having an anion group in each molecule, and a polymer compound T containing amidinium cations B expressed by Chemical Formula (1) as an indispensable constitutional unit.