Our interests are in detecting the spatial pattern of Phyllostachys nigra culms within growth stages-sprouts, current-year culms, and 5-year-old culms- and discussing the changes among them. The analysis used Ripley's univariate L(t) function. Change in the spatial pattern among growth stages was not observed in the intermediate and edge parts of bamboo forest where culms were less aggregated from early stage. In the interior, sprouts and current-year culms had clumped distribution at almost all distances in years with high annual culm production. Spatial pattern changes were observed from a clumped distribution of current-year culms into a less aggregated distribution of 5-year-old culms. We infer that the density is a determinant in forming the spatial pattern of culm stage of P. nigra v. henonis through competition in the stand with high density culms.