A controller of a battery monitoring apparatus, said controller calculating the amount of heat generated inside a battery on the basis of information about the electric current which flows out of or flows into the battery. Furthermore, the controller calculates the amount of heat discharged from the surface of the battery, said amount being calculated on the basis of temperature information about at least one from among the surface of the battery and a substance in the vicinity of the battery. In addition, the controller calculates the temperature inside the battery on the basis of information about the amount of heat generated, and information about the amount of heat discharged.