An angular contact ball bearing comprising: an outer ring which includes an outer ring raceway surface on an inner peripheral surface thereof; an inner ring which includes an inner ring raceway surface on an outer peripheral surface thereof; a plurality of balls which are arranged rotatably with a predetermined contact angle (θ) between the outer ring raceway surface and the inner ring raceway surface; a cage which is configured to hold the plurality of balls rotatably; and a non-contact type sealing member (15, 16) which is provided at least on a bearing back surface side and which is configured to cover an opening between the outer ring and the inner ring, wherein the inner ring includes a counter bore which is formed on the bearing back surface side with respect to the inner ring raceway surface, and a minimum outer diameter of the counter bore is smaller than an outer diameter of a shoulder portion which is provided on a bearing front surface side with respect to the inner ring raceway surface, wherein the sealing member fixed to the bearing back surface side of the outer ring includes: a disk portion; and at least one annular inclined portion inclined linearly or curvedly inward in a radial direction from the disk portion toward an axial center of the angular contact ball bearing, wherein a maximum diameter of the inclined portion on an axial direction inner surface side of the sealing member is smaller than an inner diameter of a bearing back surface side end surface of the cage, characterized in that a maximum diameter of the inclined portion on an axial direction outer surface side of the sealing member is larger than the outer diameter of the shoulder portion on the bearing front surface side of the inner ring. an outer ring which includes an outer ring raceway surface on an inner peripheral surface thereof; an inner ring which includes an inner ring raceway surface on an outer peripheral surface thereof; a plurality of balls which are arranged rotatably with a predetermined contact angle (θ) between the outer ring raceway surface and the inner ring raceway surface; a cage which is configured to hold the plurality of balls rotatably; and a non-contact type sealing member (15, 16) which is provided at least on a bearing back surface side and which is configured to cover an opening between the outer ring and the inner ring, wherein the inner ring includes a counter bore which is formed on the bearing back surface side with respect to the inner ring raceway surface, and a minimum outer diameter of the counter bore is smaller than an outer diameter of a shoulder portion which is provided on a bearing front surface side with respect to the inner ring raceway surface, wherein the sealing member fixed to the bearing back surface side of the outer ring includes: a disk portion; and at least one annular inclined portion inclined linearly or curvedly inward in a radial direction from the disk portion toward an axial center of the angular contact ball bearing, wherein a maximum diameter of the inclined portion on an axial direction inner surface side of the sealing member is smaller than an inner diameter of a bearing back surface side end surface of the cage, characterized in that a maximum diameter of the inclined portion on an axial direction outer surface side of the sealing member is larger than the outer diameter of the shoulder portion on the bearing front surface side of the inner ring. a disk portion; and at least one annular inclined portion inclined linearly or curvedly inward in a radial direction from the disk portion toward an axial center of the angular contact ball bearing, wherein a maximum diameter of the inclined portion on an axial direction inner surface side of the sealing member is smaller than an inner diameter of a bearing back surface side end surface of the cage, characterized in that a maximum diameter of the inclined portion on an axial direction outer surface side of the sealing member is larger than the outer diameter of the shoulder portion on the bearing front surface side of the inner ring.