It is how possible to perform precise intensity-modulated radiation therapy (IMRT) thanks to modern radiation apparatus and innovation of computer technology. However, it needs very time-consuming procedures such as difficult treatment planning, examination of complex beam data, precise registration before treatment, and beam delivery of multiple various beams with intensity-modulated beams. Helical tomotherapy is designed to deliver intensie IMRT with several sophisticated techniques, and the machine reduces the time and procedures required to prepare and deliver IMRT. In Aichi Cancer Center Hospital, helical tomotherapy was used to deliver IMRT for patients with head and neck cancer from June 2006. We report here our clinical experience of 56 cases head and neck cancer treated with helical tomotherapy in our first year.