To provide a genetically-modified vaccinia virus that is effective for the prevention or treatment of cancer. Specifically, the present invention provides: a vaccinia virus containing two polynucleotides which are a polynucleotide that codes for IL-7 and a polynucleotide that codes for IL-12; a combination kit including two vaccinia viruses which are a vaccinia virus containing a polynucleotide that codes for IL-7 and a vaccinia virus containing a polynucleotide that codes for IL-12; and a combination use of the two vaccinia viruses.