The object of the present invention is to improve the resilience and the durability of the golf ball to be obtained by reducing the content of trans-1,4-bond in a one-piece golf ball using a polybutadiene having a high content of cis-1,4-bond. The one-piece golf ball of the present invention is obtained by molding a rubber composition containing (a) a base rubber containing a polydiene obtained by polymerizing diene in the presence of a catalyst containing a metallosalen complex and aluminoxane, (b) a co-crosslinking agent, and (c) a crosslinking agent.