PURPOSE: To obtain a relatively cheap multiple-process gas chromatograph by providing a device which conrols each sampling means and each analyzing unit, selectively takes in the output from the analyzing unit in each system, and outputs a correct analyzing result.

CONSTITUTION: The same sample is picked out from a process 11 by sampling means 121W12n, and supplied to analyzing units 131W13n respectively. An analysis control device 26 controls n units, analyzes chromatogram signals, and outputs the signal having a correct analyzing result to an interface unit 15. Chromatogram signals inputs to input devices 271W27n of the device 26 comprising a micro computer are successively taken into a processor 29 through a multiplexer 28, and stored in a memory 31. The parameter for analysis procedure is sent from a setting 32 to the memory 31, and held. The processor 29 reads out parameters in the memory 31, and transmits them as a sampling means control signal 34 and an analyzing unit control signal 35 through an output device 33.