Strong electric fields inside thunderclouds can accelerate electrons to relativistic energies. Gamma-ray glow is a high-energy atmospheric phenomenon originating from bremsstrahlung of the accelerated electrons. Since they originate from electric fields inside thunderclouds rather than lightning flashes, gamma-ray glows are not usually coincident with lightning flashes. On the other hand, gamma-ray glows are sometimes terminated with lightning flashes as lightning flashes can discharge the electrified region. Therefore, lightning mapping observation is useful to investigate how the electrified region is depleted by lightning flashes. On December 18, 2018, we detected a gamma-ray glow at Kanazawa University in Japan during a wintertime thunderstorm. Winter thunderstorms along the coast of the Sea of Japan are an ideal target for observing gamma-ray glows as their charge center is lower than summer thunderstorms and hence high-energy particles are less attenuated before reaching the ground. The gamma-ray glow was terminated by a lightning flash that was monitored by the Fast Antenna Lightning Mapping Array. Combining the gamma-ray and lightning mapping observations, we discuss the charge structure of the thundercloud that produced the gamma-ray glow.