A charge and discharge control device configured to control charging and discharging of a plurality of batteries (11, 1000) configured to be removably connected in parallel to a power consumption element, the charge and discharge control device comprising: a required power input component to which is configured to be inputted a request for power to be supplied to a drive source of the power consumption element; a remaining capacity acquisition component configured to acquire remaining capacity of each of the batteries (11, 1000); a priority setting component configured to set priority of use of the plurality of batteries (11, 1000) when supplying the power inputted to the required power input component, on the basis of the remaining capacity acquired by the remaining capacity acquisition component, a battery use decision component configured to decide on one or more batteries (11, 1000) to use out of the plurality of batteries (11, 1000), on the basis of the priority set by the priority setting component and the power inputted to the required power input component; and a connection relation decision component configured to decide on an electrical connection relation between the plurality of batteries (11, 1000) and the drive source of the power consumption element so as to supply power from the one or more batteries (11, 1000) decided to be used by the battery use decision component to the drive source, wherein, when the remaining capacity of the battery (11, 1000) whose priority is high is presumed to have reached a first threshold on the basis of the remaining capacity acquired by the remaining capacity acquisition component, the priority setting component lowers the priority of that battery (11, 1000) and raises the priority of the other battery (11, 1000), and when the remaining capacity of the battery (11, 1000) has reached a second threshold that is below the first threshold, the connection relation decision component decides on the electrical connection relation so that power is supplied from the other battery (11, 1000) whose remaining capacity is above the first threshold, to the batteries (11, 1000) whose remaining capacity has reached the second threshold. a required power input component to which is configured to be inputted a request for power to be supplied to a drive source of the power consumption element; a remaining capacity acquisition component configured to acquire remaining capacity of each of the batteries (11, 1000); a priority setting component configured to set priority of use of the plurality of batteries (11, 1000) when supplying the power inputted to the required power input component, on the basis of the remaining capacity acquired by the remaining capacity acquisition component, a battery use decision component configured to decide on one or more batteries (11, 1000) to use out of the plurality of batteries (11, 1000), on the basis of the priority set by the priority setting component and the power inputted to the required power input component; and a connection relation decision component configured to decide on an electrical connection relation between the plurality of batteries (11, 1000) and the drive source of the power consumption element so as to supply power from the one or more batteries (11, 1000) decided to be used by the battery use decision component to the drive source, wherein, when the remaining capacity of the battery (11, 1000) whose priority is high is presumed to have reached a first threshold on the basis of the remaining capacity acquired by the remaining capacity acquisition component, the priority setting component lowers the priority of that battery (11, 1000) and raises the priority of the other battery (11, 1000), and when the remaining capacity of the battery (11, 1000) has reached a second threshold that is below the first threshold, the connection relation decision component decides on the electrical connection relation so that power is supplied from the other battery (11, 1000) whose remaining capacity is above the first threshold, to the batteries (11, 1000) whose remaining capacity has reached the second threshold.