Cognomen 西部 (西部 
, Nishibe 
, Саибу) , throughout the world, is a very rare last name. The cognomen 西部 is habitual in Brazil, where it is a very rare surname, Argentina, and China, where it is an extremely rare surname. Not in comparison with a country's population, the name is most common in Brazil, China, and the United States. Likewise, 西部 is the forename as well as the last name.