There is disclosed a battery monitoring device including a voltage equalization circuit that equalizes cell voltages of a plurality of battery cells being connected in series and forming a battery pack, and a microcomputer that outputs an instruction signal to instruct the voltage equalization circuit to start an voltage equalizing operation for the battery cells. The microcomputer includes a first timer section that stops the voltage equalizing operation a first predetermined set time after the start of the voltage equalizing operation, and the voltage equalization circuit includes a second timer section that stops the voltage equalizing operation a second predetermined set time after the start of the voltage equalizing operation. This can enhance reliability during the voltage equalizing operation.