The present invention is related to a bispecific antibody or an antibody fragment thereof comprising an antigen binding domain that binds to a TRAILR2, and an antigen binding domain that binds to a PSMA; a nucleic acid comprising a nucleotide sequence that encodes the antibody or the antibody fragment thereof; a recombinant vector comprising the nucleic acid; a transformant comprising the recombinant vector; a method for producing the bispecific antibody or the antibody fragment thereof by using the transformant; and a reagent for detection or measurement, a diagnostic agent, and a therapeutic agent, each of which comprises the bispecific antibody or the antibody fragment thereof.