In order to find out the basic factors governing the rooting ability of pine cutting, the rooting of cuttings of Pinus thunbergii were examined under various conditions. A total of 5 different solutions of growth hormones made up of 3-indole butyric acid, naphthalene acetic acide and rootone were employed at three different periods of year, the middle of June, the end of September and the early of December. Cuttings prepared in length of 4cm gave better results than those of control ones. Cuttings taken from the 1-0 seedlings were superior to those from the 7-year-old trees. Seasonal variation, i.e., time of collecting cutting materials, played great important role on rooting. The majority of roots were originated from the callus lamp formed at the base of cut surface.