The present inventors constructed a DNA expression vector encoding 2D7sc(Fv)2 in which the heavy chain variable region sequence (VH) and the light chain variable region sequence (VL) of the 2D7 antibody is arranged in the order of VH-VL-VH-VL, and these sequences are linked by a 15-mer linker. The vector was introduced into CHO cells and a 2D7sc(Fv)2-producing expression cell line was established. When 2D7sc(Fv)2 was expressed in this cell line, purified, and cell death-inducing experiments performed, 2D7sc(Fv)2 was found to have a concentration-dependent cell death-inducing activity.