Since the discovery of cosmic rays, the time series data of arrival time intervals of cosmic rays have been considered to be the typical example of random number. By the correlation dimension analysis for about 5 million time series data of air showers, it is found that the successive high energy cosmic rays arriving from the direction concerning to the Galactic plane have usually the chaotic feature. The origin of the chaos of cosmic rays is assumed to be the evolution of magnetic field in the Galaxy. Moreover, the chaotic feature of the high energy cosmic rays seem to be sensitive to the dark-matter.