The present invention addresses the problem of providing: an anti-tumor agent having a superior anti-tumor effect compared with a therapy with gemcitabine, paclitaxel or a combination thereof； an anti-tumor kit； and an anti-tumor effect enhancer. According to the present invention, an anti-tumor agent is provided, which comprises paclitaxel or a salt thereof and 1-(2-deoxy-2-fluoro-4-thio-β-D-arabinofuranosyl)cytosine or a salt or prodrug thereof.
