A device controls charging a battery with power supplied from a power supply located outside of a vehicle through a charge cable. The device includes a first microcomputer and a second microcomputer. The first microcomputer is configured to turn on a charge mode signal upon detecting a change in a pilot signal output through the charge cable, and to turn off the charge mode signal when a charge completion signal output from the second microcomputer is turned off. The second microcomputer is configured to charge the battery through the charge cable when the charge mode signal is turned on, and to turn off the charge completion signal when the charging is complete. When the charge completion signal is turned on at the time of the first microcomputer turning off the charge mode signal due to sudden fluctuations, the charge mode signal is turned on again.