To provide a turbo compressor supplying an appropriate amount of lubricating oil depending on operational statuses.

In the turbo compressor, a rotational shaft is rotatably supported by a housing through rolling bearings and is variably rotated by a driving source, and at least one end of the rotational shaft is provided with impellers. The rolling bearing is an under-raceway lubrication type rolling bearing in which lubricating oil is supplied into the bearing along an inner ring by a centrifugal force. The rolling bearing is provided with an oil supply mechanism adjusting a supply amount of lubricating oil to be supplied into the bearing. The oil supply mechanism is controlled to supply a very small amount of lubricating oil smaller than the lubricating oil amount supplied into the rolling bearing by the centrifugal force, when a revolution number of the rotational shaft is not more than a first revolution number N1.