PURPOSE: To supply the clock of the same phase to respective element processors so that the respective element processors are synchronously operated on a parallel computer having multiple element processors.

CONSTITUTION: The respective element processors 3-5 connected in serial are composed by providing phase difference detection parts 6 which fetch the clock generated by a main oscillator 1 from both transmission lines branched with a folded point as a boundary and which obtain the middle point of the phase differences of the clocks fetched from both transmission lines, and clock oscillation parts 7 generating the clock based on the obtained middle point.