A power management device includes: a calculating unit that calculates the number of parking allowed days of a vehicle, based on information about the battery state and information about the current to be consumed by the vehicle while the vehicle is parked; an obtaining unit that obtains a response indicating the number of parking days from the user in reply to a notification of the number of parking allowed days; and a control unit that causes a notifying unit to notify the user of the number of parking allowed days calculated by the calculating unit, and prohibits an engine stop until the charge amount of the battery reaches the necessary charge amount through a charging operation, when a determining unit determines that the battery needs to be charged in accordance with the number of parking allowed days and the number of parking days obtained by the obtaining unit.