A gas chromatography analysis method includes separating a component in sample gas by introducing the sample gas into a separation column (4) using carrier gas, and detecting a component in sample gas that has passed through the separation column (4) by introducing the sample gas into a detector (6). The detecting includes individually taking out hydrogen gas and oxygen gas generated by electrolysis of water, and controlling flow rates of taken-out hydrogen gas and oxygen gas and supplying the taken-out hydrogen gas and oxygen gas to the detector as detector gas.