An in-vehicle exhaust gas analysis system, which is provided with a flowmeter, and an exhaust gas analyzer to analyze a concentration of a measurement target component contained in exhaust gas, includes a standard gas supply mechanism to supply a standard gas containing a predetermined component to the flowmeter and the exhaust gas analyzer. The system is configured to include a detected mass calculation section to calculate a detected mass of a predetermined component by using a flow rate obtained by the flowmeter and a concentration of the predetermined component obtained by the exhaust gas analyzer, a supply mass acquisition section to acquire a supply mass of the predetermined component supplied from the standard gas supply mechanism to the flowmeter and the exhaust gas analyzer, and a mass comparison section to compare a detected mass calculated by the mass calculation section and a supply mass acquired by the supply mass acquisition section.