I describe bridging behavior and social relationships between adult males and infants in a free- ranging group of Tibetan macaques (Macaca thibetana)at Mt. Huangshan, China. The subjects performed bridging in which two adult males simultaneously lifted up an infant, sucked or touched its genitalia, and then groomed each other in nonagonistic contexts. Males also expressed social behaviors with other males, such as mounting, penis-sucking, and embracing while touching each other’s penes. Males also employ bridging while exploiting an infant as a social tool, not only to reduce the probability of an aggressive response from dominant males (agonistic buffering), but also to develop and to maintain affiliative social relationships with other males. Use of male infants in bridging contributed to frequent male-infant interactions such as holding,grooming, and penis-sucking. Although these interactions might not have a positive influence on infant survival, they may facilitate the maintenance of affiliative relationships with adult males until they reach maturity. The development of bridging might have a close relation to the high socionomic sex ratio (adult male/adult female) and frequent affiliative interactions between males, especially among the adolescents and adults.