The present invention is a sample gas analysis device that reduces a measurement error due to a coexistence influence of another measurement target component different from the measurement target component, analyzes a concentration of a plurality of measurement target components in a sample gas by performing multivariate analysis using a spectroscopic spectrum obtained by irradiating the sample gas with light, and includes a library data storage configured to store library data including a plurality of spectrum data corresponding to a plurality of the measurement target components used for the multivariate analysis, and a concentration calculator configured to calculate the concentration of the plurality of measurement target components in the sample gas by the multivariate analysis using the plurality of library data stored in the library data storage, in which the plurality of measurement target components includes a first measurement target component and a second measurement target component that coexist, and the library data storage stores, as part of the plurality of spectrum data, at least one of coexistence influence spectrum data of the first measurement target component having a spectrum shape changed due to a coexistence influence or coexistence influence spectrum data of the second measurement target component.