Charm-pair productions are investigated phenomenologically in νN, µ-N and pN reactions. Neutrino-induced same-sign dimuons are well described by assuming a sizable c-c production in the hadron shower. Then, it is shown that this assumption can be checked by searching for νN→µ-e-X process and µ-N→µ-µ±X process in the large x region, and is not inconsistent with the data on pN→ccX reaction. As to the last reaction, however, it is also argued that it is difficult at present to do a clean test of this assumption.