An electric power management system, comprising a vehicle including a battery, and an electric power management device configured to manage electric power in a building and further configured to be electrically connectable to the vehicle, the electric power management device comprises: a command issuing unit (S1320; S1520) configured to issue a command to perform charging and discharging of the battery; a specifying unit configured to specify a target range for a charging rate of the battery in performing the charging and discharging; and a storage unit (S1100, S1360, S1560) configured to store the charging rate of the battery in performing the charging and discharging, the vehicle further comprises: a charge-and-discharge unit configured to be able to perform charging from the building to the battery and discharging from the battery to the building; characterized in that the vehicle further comprises: an auxiliary battery configured to be charged by receiving an electric power from the battery and store the electric power; and a control unit configured to control driving of the charge-and-discharge unit wherein the control unit is brought into an operating state by receiving electric power of the auxiliary battery, the command issuing unit (S1320, S1520) causes the control unit to operate in the operating state in a case of issuing the command to perform the charging and discharging, and suppresses the operation of the control unit by entering in a suspended state in a case of restraining an issuance of a command to start the discharging or an issuance of a command to start the charging, wherein the suspended state implies that the consumption of the electric power of the auxiliary battery is suppressed in a case where the charging rate stored in the storage unit (S1100, S1360, S1560) is not more than a lower-limit value of the target range, the command issuing unit restrains an issuance of a command to start discharging of the battery, and in a case where the charging rate is not less than an upper-limit value of the target range, the command issuing unit (S1320, S1520) restrains an issuance of a command to start charging of the battery. a command issuing unit (S1320; S1520) configured to issue a command to perform charging and discharging of the battery; a specifying unit configured to specify a target range for a charging rate of the battery in performing the charging and discharging; and a storage unit (S1100, S1360, S1560) configured to store the charging rate of the battery in performing the charging and discharging, a charge-and-discharge unit configured to be able to perform charging from the building to the battery and discharging from the battery to the building; an auxiliary battery configured to be charged by receiving an electric power from the battery and store the electric power; and a control unit configured to control driving of the charge-and-discharge unit wherein the control unit is brought into an operating state by receiving electric power of the auxiliary battery, the command issuing unit (S1320, S1520) causes the control unit to operate in the operating state in a case of issuing the command to perform the charging and discharging, and suppresses the operation of the control unit by entering in a suspended state in a case of restraining an issuance of a command to start the discharging or an issuance of a command to start the charging, wherein the suspended state implies that the consumption of the electric power of the auxiliary battery is suppressed in a case where the charging rate stored in the storage unit (S1100, S1360, S1560) is not more than a lower-limit value of the target range, the command issuing unit restrains an issuance of a command to start discharging of the battery, and in a case where the charging rate is not less than an upper-limit value of the target range, the command issuing unit (S1320, S1520) restrains an issuance of a command to start charging of the battery.