There is provided a novel transition metal phosphine complex having excellent anticancer activity. The transition metal phosphine complex is represented by general formula (1):(wherein R1s and R3s each represent an alkyl group, a cycloalkyl group, an aryl group, an aralkyl group, a pyridyl group, or a pyrimidyl group R2s and R4s each represent an alkyl group or a cycloalkyl group, provided that each R1 and each R2 are not the same group and that each R3 and each R4 are not the same group As each represent a linear alkylene group or a cis-vinylene group M represents a gold atom, a silver atom, a copper atom, or a platinum atom and B represents an anionic species).
