In Japan, the number of cases of Trauma-Focused Cognitive Behavioural Therapy（TF-CBT）in outpatient settings is increasing, but there are very few reports of TF-CBT in inpatient settings. We report a case of a patient with post-traumatic stress disorder and neurodevelopmental disorder who was effectively treated with inpatient TF-CBT in a child psychiatric ward. The patient was a 12-year-old boy who had experienced trauma in his childhood and was admitted to hospital because of frequent problematic behaviours. We conducted TF-CBT and the patient's trauma symptoms improved and the frequency of problematic behaviours decreased. We consider that the advantages of providing TF-CBT in inpatient treatment include ensuring the safety and security of the child, providing immediate feedback on trauma symptoms, ensuring the acquisition of learned coping skills, and providing life support in collaboration with ward staff. On the other hand, we consider that a disadvantage is that parents may have insufficient opportunities to practice parenting skills.