A stochastic gravitational wave background (SGWB) is a weak and persistent background of gravitational waves (GWs) and can provide valuable insights into the origins and evolution of the universe. To detect the SWGB, cross-correlations between multiple GW detectors are calculated and local noise is canceled; however, global coherent noises, such as the Schumann resonance, remain and affect the observation. The Schumann resonance is a natural phenomenon in which the Earth’s electromagnetic field resonates at extremely low frequencies (ELF wave) of approximately 8, 14, 20 Hz, etc. This frequency range is similar to the wavelength of the Earth’s circumference and is generated by the interaction of lightning discharges in the ionosphere and the Earth’s surface. To evaluate the characteristics of the Schumann resonance, we have introduced a setup for Schumann resonance observations at the entrance of the KAGRA site and evaluate the temporal variation of the spectrum. Its effect on SGWB search based on our data is estimated using the Fisher matrix formalism.