The origin is an altar for the harvest festival held during times when Japanese continuously migrated from one place to the next to hunt wild life and gather food to sustain their lives and, in those days, the mikoshi was taken down after the festival and, every year, a new mikoshi was built to invite a god to come down from heaven.
狩猟と採集による移住を繰り返した時代に行われた収穫祭の祭壇が起源で、このときは祭りが終わると神輿は取り壊され、毎年新たな神輿を作って天上の神を招いていた。