The goal of the hadron physics is to understand the origin of the mass of the matter and mechanism of the confinement of quarks. Baryons which contain heavy quark(s) are good probes to study the interaction of the quarks inside the hadron. Because its motion inside the hadron is rather small, the non-relativistic potential approach is a good approximation for the interaction of heavy quarks. Currently, no doubly charmed baryon (Ξcc) is established experimentally although its existence is predicted by the constituent quark model.  In this talk, the result of the Ξcc search at Belle experiment and other results related to charmed baryons are presented.