An information processing system having an original clock oscillator for delivering at least one original clock signal K defined as a first clock signal and a plurality of information processing units supplied with the original clock signal K, wherein each information processing unit comprises clock generating means for generating at least one second clock signal K.sub.1 which is phase-locked with the original clock signal K and which has a predetermined duty cycle and a logic device whose operation timing is controllled by the second clock signal K.sub.1, and the operation timing of an interface provided between at least one pair of logic devices is synchronously controlled by the clock signal K.sub.1.