An electric vehicle including a vehicle body, an on-board battery mounted on the vehicle body, and an electric motor supplied with electric power from the on-board battery, the electric vehicle being driven by the electric motor to travel, wherein the vehicle body includes a battery receiving portion for releasably receiving the on-board battery, the battery receiving portion having vehicle-body-side feeding terminals disposed on a bottom thereof for supplying electric power of the on-board battery to a vehicle body side, wherein the on-board battery has battery-side feeding terminals disposed on a bottom surface thereof for mating with the vehicle-body-side feeding terminals of the battery receiving portion, and wherein the on-board battery has a charge portion disposed on one lateral surface thereof for allowing an external power supply to charge the on-board battery, the one lateral surface facing one of left and right sides of the vehicle body, characterised in that the on-board battery has a discharge portion (54; 55) disposed on an opposite lateral surface for supplying an electric power of the on-board battery to an outside, the opposite lateral surface facing the other of the left and right sides of the vehicle body, and wherein the on-board battery has a transformer (86; 87) incorporated therein for transforming electric power and/or converting DC to AC, and wherein the vehicle body includes lateral surfaces having a charge side opening for allowing a plug or a connector to pass through the charge side opening into connection to the charge portion, and a discharge side opening for allowing a plug or a connector to pass through the discharge side opening into connection to the discharge portion. wherein the vehicle body includes a battery receiving portion for releasably receiving the on-board battery, the battery receiving portion having vehicle-body-side feeding terminals disposed on a bottom thereof for supplying electric power of the on-board battery to a vehicle body side, wherein the on-board battery has battery-side feeding terminals disposed on a bottom surface thereof for mating with the vehicle-body-side feeding terminals of the battery receiving portion, and wherein the on-board battery has a charge portion disposed on one lateral surface thereof for allowing an external power supply to charge the on-board battery, the one lateral surface facing one of left and right sides of the vehicle body, characterised in that the on-board battery has a discharge portion (54; 55) disposed on an opposite lateral surface for supplying an electric power of the on-board battery to an outside, the opposite lateral surface facing the other of the left and right sides of the vehicle body, and wherein the on-board battery has a transformer (86; 87) incorporated therein for transforming electric power and/or converting DC to AC, and wherein the vehicle body includes lateral surfaces having a charge side opening for allowing a plug or a connector to pass through the charge side opening into connection to the charge portion, and a discharge side opening for allowing a plug or a connector to pass through the discharge side opening into connection to the discharge portion.