An anticancer agent having a novel chemical structure and high anticancer activity is provided. A phosphine transition metal complex of general formula (1) and an anticancer agent containing the complex are disclosed.R1 and R2, which may be the same or different, each represent a group having 1 to 10 carbon atoms selected from a straight-chain or branched alkyl group, a cycloalkyl group, a substituted cycloalkyl group, an adamantyl group, a phenyl group, and a substituted phenyl group R3 and R4, which may be the same or different, each represent a hydrogen atom, a straight-chain alkyl group having 1 to 6 carbon atoms or branched alkyl group having 1 to 6 carbon atoms or R3 and R4 are taken together to form a saturated or unsaturated ring which may have a substituted group M represents a transition metal atom selected from the group consisting of gold, copper, and silver and X− represents an anion.
