To develop a yellow pigment for a food-additive, a strain producing a water-soluble yellow pigment was isolated from phylloplane of tree leaf. The strain PY123 was identified a Bacillus sp. based on morphological and biochemical characterization such as a bacillus form, mortility, spore formation, Gram positive, and catalase production. The pigment production of the strain PY123 was increased about 3 times in patato broth containing 1% sucrose and 0.1 mM CoCl$_{2}$ than in only potato broth after incubation at 30$circ$C, for 2 days. When 0.1 mM CoCl$_{2}$, was added in potato broth containing 1% sucrose at late log phase during incubation of the strain PY123, cell growth was not inhibited, and the period at maximal pigment production of the strain PY123 was about 12hrs faster than in potato broth containing 1% sucrose and 0.1 mM CoCl$_{2}$, simultaniously.