A vehicle door opening/closing device includes a front door configured to open and close a front left opening of a vehicle body, a rear sliding door configured to open and close a rear left opening of the vehicle body, a vehicle door opening/closing device main body configured to automatically open and close the rear sliding door, a detection unit configured to detect the presence of the left foot of a user, and a control unit (detection ECU, door lock ECU, sliding door driving ECU). If the front door is in an opened state at the time when the detection unit detects the presence of the left foot, the control unit does not put the rear sliding door into a closed state.