A spindle system provided with a substantially tubular housing, a rotary shaft inserted through the housing and supported through a bearing in a rotatable manner, a turbine impeller provided concentrically with the rotary shaft and rotating integrally with the rotary shaft, a nozzle ejecting a gas for making the turbine impeller rotate, and a plurality of turbine blades formed at the turbine impeller and receiving the gas ejected from the nozzle, characterized in that the following five conditions A, B, C, D, and E are satisfied: Condition A: The plurality of turbine blades are arranged in a ring along an outer circumference of the turbine impeller, and the intervals between adjoining turbine blades are equal intervals. Condition B: Each turbine blade is provided with a front surface oriented to a front in a rotational direction of the turbine impeller and a rear surface oriented to a rear in a rotational direction of the turbine impeller. Condition C: The rear surface is a recessed columnar surface having a radius of curvature R1, while the front surface is a smooth continuous surface consisting of a projecting columnar surface having a radius of curvature R3 smaller than R1, arranged between a projecting columnar surface having a radius of curvature R2 larger than R1 and a flat surface. Condition D: A space sandwiched between a facing front surface and rear surface of two adjoining turbine blades forms a channel through which the gas flows in a direction along an arc-shaped curve of the recessed columnar surface, and gas ejected from the nozzle flows in from an opening at one end side of the channel, flows in at a direction along the arc-shaped curve of the recessed columnar surface, and flows out from an opening at another end side. Condition E: The projecting columnar surface having a radius of curvature R2 among the three surfaces forming the front surface is arranged at an inlet side of the channel across the projecting columnar surface having a radius of curvature R3, and the flat surface is arranged at an outlet side of the channel. Condition A: The plurality of turbine blades are arranged in a ring along an outer circumference of the turbine impeller, and the intervals between adjoining turbine blades are equal intervals. Condition B: Each turbine blade is provided with a front surface oriented to a front in a rotational direction of the turbine impeller and a rear surface oriented to a rear in a rotational direction of the turbine impeller. Condition C: The rear surface is a recessed columnar surface having a radius of curvature R1, while the front surface is a smooth continuous surface consisting of a projecting columnar surface having a radius of curvature R3 smaller than R1, arranged between a projecting columnar surface having a radius of curvature R2 larger than R1 and a flat surface. Condition D: A space sandwiched between a facing front surface and rear surface of two adjoining turbine blades forms a channel through which the gas flows in a direction along an arc-shaped curve of the recessed columnar surface, and gas ejected from the nozzle flows in from an opening at one end side of the channel, flows in at a direction along the arc-shaped curve of the recessed columnar surface, and flows out from an opening at another end side. Condition E: The projecting columnar surface having a radius of curvature R2 among the three surfaces forming the front surface is arranged at an inlet side of the channel across the projecting columnar surface having a radius of curvature R3, and the flat surface is arranged at an outlet side of the channel.