A patient with left hemiplegia following cerebral infarction could not maintain a sitting position. Treatment in this position was difficult for the patient because of a tendency to fall toward the paralyzed side (left side) when sitting, and associated anxiety. Therefore, with the aim of maintaining the sitting position, physiotherapy was started in this position for a week to treat hypotonia of the internal and external oblique muscles of the abdomen, longissimus muscle, and multifidus muscle, which was the primary condition. However, it was difficult to maintain a sitting position. Thus, we considered that it was necessary to treat hypotonia by placing the patient in a supine position to improve the ability to maintain the sitting position. After 3 days of practicing to turn to the non-paralyzed side (right side), and sitting-up exercises to increase the activity of the internal and external oblique muscles of the abdomen, longissimus muscle, and multifidus muscle, the patient was able to sit independently without support. To treat the condition and help maintain a sitting position, as well as to reduce the anxiety of falling, it is necessary to initially treat the patient in a supine position.