As a basis to make clear the relationship between scoring occurrence and temperature in spur gears, the temperature rise of a rectangular-shaped body used as the model of a gear tooth was examined analytically when a moving heat source with variational heat quantity acted repeatedly at regular intervals. The characteristics of the temperature rise of the body and the effects of radiation on the temperature rise were investigated. The temperature rise of the working flank in the heat supply region and its neighborhood can be divided into the flash temperature component not affected by the state of radiation and the bulk temperature rise component markedly affected by it.