A power management device for vehicles includes a communication control section that performs interactive communication to selectively supply and receive the electric power with respect to the external power source device and a supplying/receiving control section that controls supplying/receiving of the electric power by the vehicle-mounted power storage device. When the condition that the supplying/receiving control section is in the great power state is satisfied, control of the supplying/receiving of the electric power is allowed. If the supplying/receiving control section is in the decreased state before the vehicle-mounted power storage device and the external power source device selectively supply and receive the electric power with respect to each other, the communication control section performs the interactive communication.