Akathisia is a condition wherein sitting calmly and quietly is impossible, with a representative complaint of restless legs. It is generally assumed to be caused by anti-dopamine activity. In severe cases, it has been known to result in suicide attempt. We reported a case of drug-induced akathisia with difficulty in oral intake, in which fentanyl citrate sublingual tablets were found to be effective in relieving symptoms. The patient was a female aged 50's who had a gastric cancer with peritoneal dissemination causing pain and vomiting. Palliative care was requested for management of symptoms. Metoclopramide and haloperidol were administered for vomiting. However, because of the complaints of restless legs, the case was diagnosed as drug-induced akathisia. Fentanyl citrate sublingual tablets were then administered for pain management, resulting in temporary improvement of akathisia symptoms.