A turning function-equipped hub unit comprising: a hub-bearing-part assembly component including a hub bearing configured to support a wheel of a vehicle; and a turning actuator, wherein the hub-bearing-part assembly component is configured to be mounted on a unit support member of a suspension device (12, 12R) for supporting the wheel so as to be rotatable about a turning axis extending in a vertical direction, and the turning actuator is configured to be mounted on the unit support member so as to rotate the hub-bearing-part assembly component about the turning axis, the hub-bearing-part assembly component is mounted on the unit support member via two rotation permitting support components provided above and below the hub-bearing-part assembly component so as to be rotatable about the turning axis, the hub-bearing-part assembly component includes the hub bearing, an outer ring, and a brake caliper attachment part that are integrally formed as a single assembly component, the outer ring includes: an annular part fitted to an outer peripheral surface of an outer race of the hub bearing; and attachment shaft parts each having a trunnion shaft shape, the attachment shaft parts being provided so as to protrude upwardly and downwardly from an outer periphery of the annular part, and each of the attachment shaft parts being provided so as to be coaxial with the turning axis, each of rolling bearings that serve as the rotation permitting support components includes an inner race, an outer race, and rolling elements arranged in double rows and interposed between the inner and outer races (4a, 4b), the inner races being fitted to the outer peripheries of the attachment shaft parts provided to the outer ring, and the outer races being fitted to bearing fitting parts provided to the unit support member, and each of the rotation permitting support components is preloaded. a hub-bearing-part assembly component including a hub bearing configured to support a wheel of a vehicle; and a turning actuator, wherein the hub-bearing-part assembly component is configured to be mounted on a unit support member of a suspension device (12, 12R) for supporting the wheel so as to be rotatable about a turning axis extending in a vertical direction, and the turning actuator is configured to be mounted on the unit support member so as to rotate the hub-bearing-part assembly component about the turning axis, the hub-bearing-part assembly component is mounted on the unit support member via two rotation permitting support components provided above and below the hub-bearing-part assembly component so as to be rotatable about the turning axis, the hub-bearing-part assembly component includes the hub bearing, an outer ring, and a brake caliper attachment part that are integrally formed as a single assembly component, the outer ring includes: an annular part fitted to an outer peripheral surface of an outer race of the hub bearing; and attachment shaft parts each having a trunnion shaft shape, the attachment shaft parts being provided so as to protrude upwardly and downwardly from an outer periphery of the annular part, and each of the attachment shaft parts being provided so as to be coaxial with the turning axis, each of rolling bearings that serve as the rotation permitting support components includes an inner race, an outer race, and rolling elements arranged in double rows and interposed between the inner and outer races (4a, 4b), the inner races being fitted to the outer peripheries of the attachment shaft parts provided to the outer ring, and the outer races being fitted to bearing fitting parts provided to the unit support member, and each of the rotation permitting support components is preloaded.