A carbon oxide sensor having high sensitivity capable of reduction of influence
of humidity is provided. A detection electrode and a counter electrode are provided
on one side of an electrolyte, respectively. The detection electrode contains a
metal oxide and a metal carbonate including plural components. The metal carbonate
preferably contains a first component of alkali metal carbonate and a second component
of at least one element selected from the group consisting of alkali earth metal
carbonate, transition metal carbonate, zinc carbonate, cadmium carbonate, indium
carbonate, lead carbonate and bismuth carbonate. Specifically, it is preferable
to contain the first component including Li2CO3 and the second
component including at least one element selected from the group consisting of
BaCO3, CaCO3 and SrCO3.
