A cancer therapeutic agent according to an embodiment of the present invention contains, as active ingredients, IL-18 and one or more antibodies selected from the group consisting of an anti-PD-L1 antibody, an anti-PD-1 antibody, an anti-PD-L2 antibody, an anti-CTLA-4 antibody, an anti-CD25 antibody, an anti-CD33 antibody, and an anti-CD52 antibody.