The Nand Flash memory that the factories will make is commonly used in consumer electronics products like digital media players, and is expected eventually to move into some of the roles currently occupied by hard disk drives.
Toshiba's investment is part of an $18bn spending package outlined by company executives at a Tokyo briefing yesterday.
Toshiba hopes that the investment will boost its total worldwide sales from $58bn last year to more than $70bn in fiscal 2009, with operating profits of $3.52bn.
Analysts were generally positive about the plans, but expressed doubts that the company's profit margin targets were easily achievable.
Toshiba's new focus on Flash memory will bring its total number of Flash production plants up to five.
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