PURPOSE: To discover the errors in setting of parameters by having a memory which stores two kinds of parameters (analyzing conditions), and determining two kinds of peak areas separately with two kinds of these parameters.

CONSTITUTION: An integrating device has a gas chromatograph, a memory which stores analyzing conditions, and an integrator 3 for peak areas. The integrator 3 has functions of determining peak areas respectively separately with two kinds of parameters 2 and 2'. A calculating section which calculates the ratio of two kinds of said areas, a quantitative calculating section 4 which calculates concn., a control section 6 for printing which prints the results, and a printer 7 are provided in this device. The operator is able to set two kinds of different analyzing conditions. Thus incorrect set values of the parameters are checked easily, and the errors in setting of the parameters are discovered easily.