A thin type fan includes an impeller and a motor. The impeller includes a hub and a blade structure disposed around the hub. The motor includes a stator structure, a magnetic assembly, a bearing structure and a rotational shaft. The motor drives the impeller to rotate. The magnetic assembly is disposed within the hub and around the stator structure. The magnetic assembly includes a magnet and a magnetically permeable shell. The bearing structure includes a bearing seat and a single ball bearing. The single ball bearing is disposed in the bearing seat and forms an accommodating space, and the rotational shaft is disposed in the accommodating space.