A sliding unit for a vehicle includes: a rail having a bottom surface, both side surfaces and a top surface, the rail configured to extend in a front-rear direction, be bent, and then extend in a left-right direction; a moving part slidably disposed on the rail to slide along the rail to move in the front-rear direction or in the left-right direction; a magnetic force part disposed in the moving part and configured to be locked to or unlocked from the rail through a magnetic force; and ground parts disposed on the moving part, electrically connected to the magnetic force part, and grounded with the rail to supply power from the rail to the magnetic force part.