Abstract: A portable turning machine includes a support placed on and fixed to a floor, a ring base supported by the support, a turning ring that is turnably supported by the ring base and arranged on an outer circumference side of a collector ring, a motor for turning ring that turns the turning ring, and a tool that is attached to the turning ring and is used for performing corrective machining of the collector ring. The ring base has a structure that is dividable into a lower dividable type ring base and an upper dividable type ring base. The turning ring has a structure that is dividable into a lower dividable type turning ring and an upper dividable type turning ring.