The present invention relates to a medical cast and, more specifically, to a functional cast comprising a fixing frame formed with the shape of the affected area of the body to cover the affected area of the body, and an air pocket layer coupled inside the fixing frame. The present invention comprises: a hard fixing frame formed with the shape of the affected area of the body to cover the affected area of the body to be worn; and an air pocket layer coupled inside the fixing frame. A plurality of ventilation holes are formed in the fixing frame and the air pocket layer. An air injection hole for injecting air in the air pocket layer is communicatably formed on the upper surface of the fixing frame. The compressed foam synthetic resin is embedded inside the air pocket layer.
