An electric vehicle with an arrangement structure of a power supply unit, the electric vehicle including a rear suspension cross member, supportively suspended from a total of four anchor points (5fl, 5fr, 5rl, 5rr) on a lower side of a floor of a vehicle body, for supporting left and right rear wheels via a suspension, the four anchor points (5fl, 5fr, 5rl, 5rr) being at front positions and rear positions of a pair of left and right side members (3l and 3r), the vehicle body being provided with the pair of left and right side members (3l and 3r) extending in a front-rear direction; a drive unit mounted on the rear suspension cross member on the lower side of the floor, and including at least a drive motor that drives the left and right rear wheels; and a power supply unit including at least a junction box that relays electric power from a driving battery and supplies the electric power to the drive motor, characterized in that the power supply unit is mounted on an upper side of the floor and the arrangement structure comprises: an upper front floor cross member and an upper rear floor cross member each provided in a region, in a front-rear direction, between two anchor points at front positions of the pair of left and right side members (3l and 3r) and two anchor points at rear positions of the side members, the upper front floor cross member and the upper rear floor cross member each extending in a left-right direction on an upper surface of the floor, wherein the power supply unit is disposed between the upper front floor cross member and the upper rear floor cross member in the front-rear direction. the electric vehicle including a rear suspension cross member, supportively suspended from a total of four anchor points (5fl, 5fr, 5rl, 5rr) on a lower side of a floor of a vehicle body, for supporting left and right rear wheels via a suspension, the four anchor points (5fl, 5fr, 5rl, 5rr) being at front positions and rear positions of a pair of left and right side members (3l and 3r), the vehicle body being provided with the pair of left and right side members (3l and 3r) extending in a front-rear direction; a drive unit mounted on the rear suspension cross member on the lower side of the floor, and including at least a drive motor that drives the left and right rear wheels; and a power supply unit including at least a junction box that relays electric power from a driving battery and supplies the electric power to the drive motor, characterized in that the power supply unit is mounted on an upper side of the floor and the arrangement structure comprises: an upper front floor cross member and an upper rear floor cross member each provided in a region, in a front-rear direction, between two anchor points at front positions of the pair of left and right side members (3l and 3r) and two anchor points at rear positions of the side members, the upper front floor cross member and the upper rear floor cross member each extending in a left-right direction on an upper surface of the floor, wherein the power supply unit is disposed between the upper front floor cross member and the upper rear floor cross member in the front-rear direction. an upper front floor cross member and an upper rear floor cross member each provided in a region, in a front-rear direction, between two anchor points at front positions of the pair of left and right side members (3l and 3r) and two anchor points at rear positions of the side members, the upper front floor cross member and the upper rear floor cross member each extending in a left-right direction on an upper surface of the floor, wherein the power supply unit is disposed between the upper front floor cross member and the upper rear floor cross member in the front-rear direction.