An objective of the present invention is to provide an adenovirus vector expressing a REIC/Dkk-3 protein at a high level and containing a DNA construct for expression of REIC/Dkk-3 DNA, wherein the DNA construct is prepared by ligating, from the 5 terminal side,(i) a CMV promoter,(ii) REIC/Dkk-3 DNA,(iii) a poly A addition sequence, and(iv) enhancers prepared by linking an hTERT (Telomerase Reverse Transcriptase) enhancer, an SV40 enhancer, and a CMV enhancer in this order.