In order to find the cause of cosmic-ray storms, the correlation of the spectral type of solar radio outbursts and cosmic-ray variations and magnetic activities is studied using data obtained from July 1957 to December 1960. Cosmic-ray storms are found to be closely associated with radio outbursts of Type IV (continuum). This result indicates that the eruption followed by the radio outburst of Type IV is the cause of cosmic-ray storms. The size of cosmic-ray and magnetic storm is compared with the heliographic longitude of the eruptions. Large magnetic storms occur after eruptions near the central meridian, while the size of the cosmic-ray storm is independent of the heliographic longitude of the eruption. From these results, a possible model of a magnetized corpuscular cloud is presented, which seems to be ejected from the sun during eruption followed by Type IV outburst. This model of the magnetic cloud consists of a large total bulk with a core and appears to be able to consistently explain not only the facts described but also other earth storms.