A proton conductor or a single ion conductor having high conductivity and a broad operation temperature range, manufacturing methods thereof and an electrochemical capacitor using it are provided. A compound having a structural part of Chemical formula 1 and a compound having a structure of Chemical formula 2 are included. X represents a protoic dissociation group, R1 represents a component including carbon, R2 and R3 represent a component including carbon or hydrogen, and n is in the range of n.gtoreq.1. By action of the .dbd.NCOH group of the compound having the structure of Chemical formula 2, protons can be dissociated from the compound having the structural part of Chemical formula 1 and migrated. Therefore, water retention becomes unnecessary, and high proton conductivity can be obtained in a broad temperature range. ##STR00001##