Patent ID: 8190334

Claim:
A rotation control device of working machine having a main body, a rotating body rotatably mounted on said main body and a working attachment provided in said rotating body so as to be raised and lowered, comprising: an electric motor for rotating and driving said rotating body; operation means for receiving an input operation of a drive instruction to said electric motor; operation amount detection means for detecting an operation amount of said operation means; speed detection means for detecting rotation speed of said electric motor; and control means for setting target speed of said electric motor on the basis of the operation amount detected by said operation amount detection means, setting target torque on the basis of a speed deviation between the target speed and the speed detected by said speed detection means, and operating said electric motor in accordance with the target torque, wherein said control means is provided with correction means for calculating a correction amount which is increased as increasing necessary torque for rotating said rotating body, said necessary torque being changed in accordance with a working state of said rotating body, and subtracting the correction amount from the target speed so as to make new target speed.