A rolling bearing device of the invention has inner rings, an outer ring, and a sealing unit having a seal case fixed to the outer ring. The seal case is internally fitted to an annular corner formed between a shoulder inner peripheral surface of the outer ring, and a seal groove in a state where the diameter of a fixed portion is reduced elastically, and is fixed to the outer ring in a state where the annular corner and an outer peripheral surface of the fixed portion are in a line contact with each other.