PURPOSE: To obtain a small-sized composite ion electrode ready for measuring plural component ions at the same time, by uniting a coated electrode element of different kinds and an ion nonsensitive film coated comparison electrode element in one body by a nonelectroconductive body.

CONSTITUTION: An ion electrode composite body 12 is formed by uniting an ion selective electrode parts 13W17 in one body by nonconductive resin etc. so that the parts 14W17 covered the surface of lead wires 151W171 by an ion selective film for different ions, is arranged centering around a comparison electrode part 13 formed with a lead wire 131 which is covered by an ion nonsensitive film 132. By this construction, a small-sized composite ion electrode ready for measuring ion components of every kind at the same time, is made.