A rolling bearing which includes an outer ring, an inner ring having a flange portion formed at one end portion thereof, a plurality of rolling elements arranged between the inner ring and the outer ring, and a sealing device, the sealing device comprising: a metal core fixed to the end portion of the outer ring, wherein the metal core includes: a cylindrical portion fitted on an outer circumferential surface of the end portion of the outer ring; a circular ring portion which extends radially inwards from the cylindrical portion and is abutted against an end face of the end portion of the outer ring; and an inward edge portion which extends further radially inwards from a radially inward end portion of the circular ring portion to protrude from an inner circumferential side of the outer ring; an elastic seal member mounted on the metal core and having a radial lip (22a, 22b) extending from the inward edge portion of the metal core so as to be brought into sliding contact with an outer circumferential of the inner ring; and an elastic shielding portion mounted on a radially outward end portion of the circular ring portion so as to extend towards the flange portion; wherein a first clearance is formed between an end face (12c1) of the flange portion, with which an axial lip of the elastic seal member is in sliding contact, and an end portion of the outer ring, characterized in that a distal end portion of the elastic shielding portion extends in a direction toward the flange portion behind the end face (12c1) of the flange portion, such that the elastic shielding portion completely shields the first clearance in radial direction and a slight second clearance is formed between a convex surface extending outwardly from an outer end portion of the end face (12c1) of the flange portion and the distal end portion of the shielding portion. a cylindrical portion fitted on an outer circumferential surface of the end portion of the outer ring; a circular ring portion which extends radially inwards from the cylindrical portion and is abutted against an end face of the end portion of the outer ring; and an inward edge portion which extends further radially inwards from a radially inward end portion of the circular ring portion to protrude from an inner circumferential side of the outer ring; an elastic seal member mounted on the metal core and having a radial lip (22a, 22b) extending from the inward edge portion of the metal core so as to be brought into sliding contact with an outer circumferential of the inner ring; and an elastic shielding portion mounted on a radially outward end portion of the circular ring portion so as to extend towards the flange portion; wherein a first clearance is formed between an end face (12c1) of the flange portion, with which an axial lip of the elastic seal member is in sliding contact, and an end portion of the outer ring, characterized in that a distal end portion of the elastic shielding portion extends in a direction toward the flange portion behind the end face (12c1) of the flange portion, such that the elastic shielding portion completely shields the first clearance in radial direction and a slight second clearance is formed between a convex surface extending outwardly from an outer end portion of the end face (12c1) of the flange portion and the distal end portion of the shielding portion.