The Frenchman is booked in to undergo a medical today after the two clubs agreed on a fee for the 30-year-old former Monaco and Lyon player.
Gunners manager Arsene Wenger is desperate for extra cover in defence, having lost four centre-backs since the end of last season and signed just one.
Squillaci, who has 21 caps for France, is expected to rival summer signing Laurent Koscielny for a starting berth alongside Thomas Vermaelen.
Sevilla confirmed they had accepted a bid from Arsenal in a statement on their website yesterday evening. It read: “Defender Sebastien Squillaci is tonight travelling to London to have a medical at Arsenal, the club he will be transferred to after an agreement was reached by the two clubs pending the results of the medical.”
Wenger is still being tipped to sign Fulham goalkeeper Mark Schwarzer before the transfer window closes next week, although that deal has not run as smoothly.
Arsenal are yet to have a bid accepted for the veteran Australia international, while Cottagers boss Mark Hughes is reluctant to sell.