The Gunners are also closing in on the signing of young German midfielder Thomas Eisfeld from Borussia Dortmund after the 19-year-old passed a medical.
The Japanese youngster had been strongly linked with a temporary move away from the Emirates for much of the January transfer window and Owen Coyle's side has won the race.
Miyaichi was tipped to make an impression at the Gunners this season after an eye-opening spell with Feyenoord last season, but he is yet to make his Premier League debut, appearing on the bench just the once.
Bolton boss Owen Coyle told the club's official website: "He's a very talented young player, who is quick and exciting. He had a great spell on loan at Feyenoord last season.
"He's a young player with tremendous promise and potential and hopefully at Bolton we can give him a platform on which he can display his qualities."
Arsenal is also close to confirming a signing of their own as Borussia Dortmund's Thomas Eisfeld, 19, has passed his medical ahead of his move to London which should be completed on transfer deadline day.