To properly treat a motor, when in trouble, based on how the motor is in trouble.

When a current flow in a motor is judged to be abnormal by an electric abnormality judging means, a driving source of a hybrid compressor is secured while preventing the stop of a travelling engine with a compressor operation keeping means. When the driving condition of the motor is judged to be abnormal by a mechanical abnormality judging means, the hybrid compressor is disconnected from the travelling engine for protecting the travelling engine from the mechanical abnormality of the hybrid compressor.