Ito played 26 times for Stuttgart this season as the club managed to finish second behind champions Bayer Leverkusen while the left-back, who can also play centrally, helped Japan reach the quarter-finals of the Asian Cup earlier this year.
"Hiroki Ito was reliability personified at VfB Stuttgart. He produced consistent performances at a top level, which attracted the attention of several big clubs," Bayern sporting director Christoph Freund said in a statement.
"Hiroki is tall, aggressive, has a strong left foot, an excellent passing game and is versatile in defence because he can play on both the left side as well as centrally."
Ito could compete for the left-back spot with Alphonso Davies but the Canada international, who has one year left on his contract, has been linked with a move to Real Madrid.
