PROBLEM TO BE SOLVED: To provide an exhalation gas analyzer which allows easy input of a formula for calculating the reference value of a metabolic function.SOLUTION: The exhalation gas analyzer comprises: metabolic function calculation means which calculates a metabolic function of an examinee on the basis of a flow rate and gas concentration formula input means which allows a user to designate and input a formula for calculating the reference value of the metabolic function by using a key board and numerical keys formula display means which displays the formula on a screen and formula storage means capable of storing plural formulas.
