A spread range control apparatus of the present invention controls a clock generator, which generates a spread spectrum clock based on setting of spread data, so as to regulate a spread range of the spread spectrum clock. The spread range control apparatus includes: a loading quantity detection module that detects a loading quantity of a loading device, which is driven in response to a clock output from the clock generator; and a spread range setting module that sets spread data, which represents a spread range corresponding to the loading quantity detected by the loading quantity detection module, in the clock generator. This arrangement effectively protects a device having operations controlled in response to a clock from adverse effects possibly arising due to spread of the clock.