Control Method for Automatic Analyzer

[Problem] To provide a control method of avoiding drop of a throughput by solvent substitution and of avoiding increase of a solvent consumption amount in a control method for an automatic analyzer including a liquid chromatograph that includes plural analysis flow passages arranged to be parallel to each other.[Solution] Which one of plural analysis flow passages 105 to 107 is to be used is determined in introducing plural separation processes using solvents whose kind is different from each other with a time lag relative to one another, and a solvent used in a next separation process executed at timing after starting the plural separation processes determined to be introduced with a time lag relative to one another and each of the solvents used in the plural separation processes determined to be introduced with a time lag relative to one another are compared. Whether or not a solvent substitution process is required for the analysis flow passages 105 to 107 used in the plural separation processes is determined, an analysis flow passage used in the next separation process out of the plural analysis flow passages 105 to 107 is determined according to the determination, and an analysis schedule is prepared.