A secondary-battery internal short detection apparatus is provided which is capable of precisely detecting an internal short being generated in a secondary-battery. In this apparatus: an electricity-quantity storage circuit stores in advance a reference electricity-quantity necessary for charging the secondary-battery from a first voltage to a second voltage; an electricity-quantity accumulation circuit measures an accumulative electricity-quantity necessary for charging the secondary-battery from the first voltage to the second voltage; and an internal short detection circuit compares the accumulative electricity-quantity measured by the electricity-quantity accumulation circuit and the reference electricity-quantity stored in the electricity-quantity storage circuit, if the accumulative electricity-quantity is larger than the reference electricity-quantity, then decides that an internal short is generated, and if the accumulative electricity-quantity is equal to, or smaller than, the reference electricity-quantity, then without deciding that an internal short is generated, rewrites the reference electricity-quantity stored in the electricity-quantity storage circuit into the accumulative electricity-quantity.