A buffer driving capability control device is provided which can suppress occurrence of radiated noise due to a load driven by large driving power in the case where loads differing in driving power are connected to one terminal. The device includes an output buffer which can switch between the driving capability for driving a load requiring large driving power and the driving capability for driving a load requiring small driving power, and also includes a control period for driving the load requiring the large driving power and a control period for driving the load requiring the small driving power, and during the respective control periods, switches the driving capability of the output buffer to the ones suitable for the corresponding loads.