Pollution of soil and underground water, including leakage of gasoline from subterranean storage, poses a significant risk to living organisms. An approach using microorganisms to remediate polluted environments is applicable to locations beneath buildings and bridges. However, no monitoring method for bioremediation activity in soil has yet been developed. It is essential to estimate biological activity in soil to proceed with remediation activity. Accordingly, we established a method that combines bacteria detection in soil using spectral analysis with the use of genetically modified bacteria that release green fluorescence with remediation activity.