Verigy said earlier it had dropped a plan to buy smaller rival LTX Credence.
Advantest is strong in memory chip testers, but faces tough competition from global leader Teradyne Inc in non-memory testers for the fast-growing smartphone market.
By acquiring Verigy, Advantest could control as much as 48 per cent of the global chip-testing market, more than Teradyne's 40 percent, an analyst at brokerage MKM Partners estimated last year.