HYBRID SYSTEM

A hybrid system which can calculate various type of more proper required torques is provided while input factors which can be used for calculating the various types of required torques are limited. A hybrid system includes a rotation sensor which detects a rotation number of an engine , at least either one of an accelerator opening-degree sensor which detects an accelerator opening degree and a rotation-number instruction unit which transmits a rotation-number signal instructing a certain rotation number to the engine , and a control unit which controls an operation of the engine . The control unit executes control of calculating a torque determining factor for determining a system required torque as the hybrid system on the basis of at least either one of the accelerator opening degree detected by the accelerator opening-degree sensor and the rotation-number signal transmitted by the rotation-number instruction unit and control of calculating the system required torque on the basis of the rotation number detected by the rotation sensor and the calculated torque determining factor.