Purpose: Helical tomotherapy (HT) is one of the radiotherapy methods that has become widespread in recent years. The aim of this study is to investigate the safety of high-dose HT for medically inoperable esophageal cancer that is unable to tolerate chemoradiotherapy. Methods: Eight patients with medically inoperable esophageal squamous cell carcinoma who cannot tolerate chemoradiotherapy were irradiated to 60 Gy at 2 Gy/fraction with HT. Results: The 1-, and 2-year overall survival rate were 75.0%, and 46.9%, respectively. The 1-, and 2-year locoregional recurrence-free survival rate ware 72.9%, and 72.9%, respectively. Three patients developed grade 2 or 3 hematological acute toxicity, and one patient developed grade 2 late pericardial effusion. Conclusions: Medically inoperable patients with esophageal cancer who cannot tolerate chemoradiotherapy might be treated safely by high-dose HT with minimal adverse events.