Provided is a double-row angular contact ball bearing for a CT scanning device, which is based on a low-cost structure that is easy to manufacture, and is capable of achieving a further increase in speed and further quietness. The double-row angular contact ball bearing (1, 11) for a CT scanning device includes an inner member (3, 31) being made up of a pair of raceway rings (3a, 3a1). The pair of raceway rings (3a, 3a1) has positioning holes (13a, 13b) into which a positioning member (14) is inserted, to thereby suppress radial decentering of the pair of raceway rings (3a, 3a1). Both the raceway rings (3a, 3a1) are fastened by a plurality of fixing bolts (16). The pair of raceway rings (3a, 3a1) has opposed end surfaces (10a, 10b) that are formed as flat surfaces, and is fastened by the fixing bolts (16) to bring the end surfaces (10a, 10b) into abutment against each other to apply a preload at a fixed position between the balls (4) and raceway surfaces (6, 7). The following relationship is set: Db/h≤0.26, where Db represents a diameter of each of the balls (4), and h represents a radial dimension from a center of each of the balls (4) to an inner diameter of the inner member (3, 31).
