A mechanism for mounting a motor driving a drum to a tub of a washing machine, and a washing machine using the same are provided. The mechanism includes a motor located on the outer surface of a tub; at least one fixing member passing through a part of the motor and then fixed to the tub to fix the motor to the tub; and at least one isolator provided between the motor and the fixing member to prevent the fixing member from directly contacting the motor to prevent the vibration of the motor from being transmitted to the tub through the fixing member.