Today, the transportation of load in the home is done mostly by the human hands and there may hurt the body due to hard labor. Therefore, we propose a load carrying robot using belt conveyor mechanism for living space. The proposed robot consists of a loading unit, a storage unit, and a body unit. A belt conveyor mechanism is used for the loading unit. We model the belt conveyor mechanism and calculate the load force and load torque. To control the speed of the belt of the belt conveyor mechanism, the rotational speed of the motor is controlled by PID control. From the simulation results, characteristics of load torque and belt velocity are observed at several conditions. The belt velocity is controlled even changing the loading weight.