Abstract: The present invention relates to a carbon dioxide measuring device, and more particularly, to a carbon dioxide measuring device in which a reference electrode signal transfer pattern is formed on one side of a heating unit to connect an electromotive lead wire for measuring carbon dioxide concentration to the outside of a portion at which the heating unit contacts a carbon dioxide sensor to thereby prevent generation of a gap, and a problem that a sealant is diffused into the reference electrode to have an effect on electromotive force is prevented to thereby increase durability and accuracy and also increase reliability of measurement of carbon dioxide concentration.