A battery charging control device for controlling a power generation device installed in an electric vehicle sets a battery energy management area using a current position of a host vehicle as a reference, detects at least one travelable route within the battery energy management area, calculates a battery energy management upper limit value and a battery energy management lower limit value on the basis of a maximum value and a minimum value of energy values required to travel to respective points on the travelable route from the current position, and calculates a battery energy management width by subtracting the management lower limit value from the management upper limit value. When the battery energy management width is not within a predetermined range, the battery energy management area is modified so as to enter the predetermined range. As a result, battery charging is controlled such that a magnitude relationship between the battery energy management upper limit value and the battery energy management lower limit value does not reverse.