Currently, cancer has become one of health problems that is difficult to be overcomed. This disease is not only difficult to be cured, but also to be detected and may cause death. For this reason, RF ablation treatment method is proposed to cure cancer. RF ablation therapy is a method in which an applicator is inserted into the body to kill cancer cells by heating the cells. The cancer cells are exposed to the temperature more than 60°C in short duration (few second to few minutes) so thus cell destruction occurs locally. For the sake of the successful treatment, a minimally invasive method is selected in order for perfect local temperature distribution in cancer cells can be achieved. In this paper, a coax-fed dipole-type applicator with interstitial irradiation technique is proposed aimed at RF ablation into hepatic cells. Numerical simulation is performed to obtain a suitable geometric dimension at operating frequency around 2.45 GHz, in order to localize the ablation area. The proposed applicator is inserted into a simple phantom representing an adult human body model in which normal and cancerous liver cells. The simulated results show that the proposed applicator is able to operate at center frequency of 2.355 GHz with blood droplet-type ablation zone and the temperature around the cancer cell by 60°C can be achieved.