To achieve cost reduction by eliminating the necessity of a guide member and a slip joint.

This vehicle seat belt device is provided with a webbing 2B, a retractor 1B provided on a vehicle body on one side of a seating part and capable of drawing out and winding up the webbing 2B, a tongue 21 provided at the drawing-out end of the webbing 2B, and a buckle 3B provided on the ceiling of the vehicle on the other side of the seating part and capable of locking the tongue 21 by drawing out the webbing 2B from the retractor 1B. By locking the tongue 21 on the buckle 3B, at least one portion of the webbing 2B is kept diagonally crossing the breast front face of an occupant M seated on the seating part to constrain the breast of the occupant M.