A drum washing machine includes a driving part which includes a driving motor, a first belt wheel fixed to a rotating shaft of a drum, a second belt wheel fixed to a rotating shaft of a rotating body, a first motor belt wheel fixed to a motor shaft of the driving motor and connected to the first belt wheel via a first transmission belt, a second motor belt wheel connected to the second belt wheel via a second transmission belt, and a clutch mechanism part configured for switching from a first driving form in which the second motor belt wheel is engaged with the clutch mechanism part so that the drum and the rotating body rotate at different speeds driven by the driving motor, and a second driving form in which the motor shaft is disconnected from the second motor belt wheel.