An object of the present invention is to provide a tumor therapeutic agent and a kit which have superior antitumor effects as compared with gemcitabine, a taxane antitumor agent, and a combination therapy thereof which have been put on the market. According to the present invention, there is provided a tumor therapeutic agent obtained by combining a taxane antitumor agent with a liposome composition in which gemcitabine or a salt thereof is contained in a liposome.