The present invention relates to an electric vehicle and a charging control method for an auxiliary battery of the electric vehicle. According to the present invention, the electric vehicle comprises: a high-voltage battery which drives the electric vehicle; a plurality of electric field loads; the auxiliary battery which supplies driving power to the plurality of electric field loads; a first voltage detection unit which detects an output voltage of an auxiliary battery side; a converter which performs a PWM switching to convert the voltage of the high-voltage battery into a voltage required in the electric field loads; a plurality of relays; a power relay assembly (PRA) which is switched to supply the energy of the high-voltage battery to the converter according to whether or not the plurality of relays are in operation; and a vehicle control module (VCM) which controls the driving of the power relay assembly, wherein the converter includes a converter control unit, which sends a driving instruction signal requesting the vehicle control module to drive the power relay assembly depending on a magnitude change of the output voltage of the auxiliary battery side. Accordingly, discharging of the auxiliary battery in a starting-off state is prevented, which makes it possible to stably operate the electric vehicle system.