A battery control apparatus comprising: a control part to control a battery pack in which a plurality of single cells are connected; a voltage measurement part (112, 130) to measure an inter-terminal voltage of each of the single cells and an inter-terminal voltage of the battery pack; characterized in that it comprises a storage part to store charging upper and lower limit values of cell voltage data of a permitted power restriction range describing a range of a closed-circuit voltage of the one single cell across which a permitted charging power is restricted from 100% to 0%, and discharging upper and lower limit values of cell voltage data of a permitted power restriction range describing a range of a closed-circuit voltage of the one single cell across which a permitted discharging power is restricted from 0% to 100%, wherein the control part is adapted to acquire the closed-circuit voltages of the single cells and the closed-circuit voltage of the battery pack measured by the voltage measurement part, acquire a present permitted charging or discharging power of the battery pack by using the closed-circuit voltage of the battery pack, set a restricted rate of the permitted charging power of the battery pack to 100% when the inter-terminal voltage of a first single cell exhibiting a maximum one of the inter-terminal voltages of said single cells is coincident with the charging lower limit value or below, set the restricted rate to 0% when the inter-terminal voltage of the first single cell is coincident with the charging upper limit value or above, and set the restricted rate to a linearly interpolated value between 100% and 0% when the inter-terminal voltage of the first single cell is between said charging lower and upper limit values, and set a restricted rate of the permitted discharging power of the battery pack to 100% when the inter-terminal voltage of a second single cell exhibiting a minimum one of the inter-terminal voltages of said single cells is coincident with the discharging upper limit value or above, set the restricted rate to 0% when the inter-terminal voltage of the second single cell is coincident with the discharging lower limit value or below, and set the restricted rate to a linearly interpolated value between 0% and 100% when the inter-terminal voltage of the second single cell is between said discharging lower and upper limit values, and control charging or discharging of the battery pack based on the present permitted charging or discharging power in accordance with the restricted rate. a control part to control a battery pack in which a plurality of single cells are connected; a voltage measurement part (112, 130) to measure an inter-terminal voltage of each of the single cells and an inter-terminal voltage of the battery pack; characterized in that it comprises a storage part to store charging upper and lower limit values of cell voltage data of a permitted power restriction range describing a range of a closed-circuit voltage of the one single cell across which a permitted charging power is restricted from 100% to 0%, and discharging upper and lower limit values of cell voltage data of a permitted power restriction range describing a range of a closed-circuit voltage of the one single cell across which a permitted discharging power is restricted from 0% to 100%, wherein the control part is adapted to acquire the closed-circuit voltages of the single cells and the closed-circuit voltage of the battery pack measured by the voltage measurement part, acquire a present permitted charging or discharging power of the battery pack by using the closed-circuit voltage of the battery pack, set a restricted rate of the permitted charging power of the battery pack to 100% when the inter-terminal voltage of a first single cell exhibiting a maximum one of the inter-terminal voltages of said single cells is coincident with the charging lower limit value or below, acquire the closed-circuit voltages of the single cells and the closed-circuit voltage of the battery pack measured by the voltage measurement part, acquire a present permitted charging or discharging power of the battery pack by using the closed-circuit voltage of the battery pack, set a restricted rate of the permitted charging power of the battery pack to 100% when the inter-terminal voltage of a first single cell exhibiting a maximum one of the inter-terminal voltages of said single cells is coincident with the charging lower limit value or below, set the restricted rate to 0% when the inter-terminal voltage of the first single cell is coincident with the charging upper limit value or above, and set the restricted rate to a linearly interpolated value between 100% and 0% when the inter-terminal voltage of the first single cell is between said charging lower and upper limit values, and set a restricted rate of the permitted discharging power of the battery pack to 100% when the inter-terminal voltage of a second single cell exhibiting a minimum one of the inter-terminal voltages of said single cells is coincident with the discharging upper limit value or above, set the restricted rate to 0% when the inter-terminal voltage of the second single cell is coincident with the discharging lower limit value or below, and set the restricted rate to a linearly interpolated value between 0% and 100% when the inter-terminal voltage of the second single cell is between said discharging lower and upper limit values, and control charging or discharging of the battery pack based on the present permitted charging or discharging power in accordance with the restricted rate.