A secondary-battery life estimation apparatus includes: a voltage measuring portion measuring a terminal voltage of a secondary battery to be measured; a first memory storing in advance a terminal voltage V0 of a non-degraded secondary battery before the non-degraded secondary battery discharges after fully charged; a second memory which stores in advance a life-estimation data map as a look-up table associating a voltage difference dV between a terminal voltage V of the secondary battery to be measured before the secondary battery to be measured discharges after fully charged and the terminal voltage V0 with a residual life of the secondary battery to be measured; and a CPU calculating the voltage difference dV between the terminal voltage V measured by the voltage measuring portion before the secondary battery to be measured discharges after fully charged and the terminal voltage V0 stored in the first memory and estimating the residual life of the secondary battery to be measured based on the life-estimation data map stored in the second memory using the voltage difference dV.