Groups of magnets are respectively provided on the joint surfaces of a vehicle-side connector and a power-supply-side connector in such a way that the N and S poles of a plurality of permanent magnets are alternately arranged in a circle. When charging is carried out, the magnetic attraction generated by placing the heteropolar magnets in both groups of magnets opposite to one another is utilized for bringing the vehicle-side connector and the power-supply-side connector into engagement with each other. After the charging, the group of magnets of the power-supply-side connector are turned by one pitch to place the homopolar magnets in both groups of magnets opposite to one another, whereby both connectors are easily separated from each other because of the magnetic repulsive force generated therebetween.