Planning Minister John Day announced the move last week.
Hitachi supplies equipment to companies like Rio Tinto, Fortescue Metals and BHP Billiton.
The minister said the company, which had outgrown its Welshpool facility, was the first to buy land in Forrestdale Business Park West, acquiring 10ha for a state-of-the-art facility.
City of Armadale Mayor Henry Zelones said he was ‘thrilled’ it had chosen Armadale.
‘Hitachi will become a landmark anchor-tenant in Forrestdale Business Park (West) and will attract associated and complementary businesses to the park,’ he said.
Mr Day said the move had already generated momentum, with a several businesses interested in co-locating with Hitachi.
He said Forrestdale Business Park’s 300ha of commercial and industrial land would allow up to 700 industrial lots, potentially providing 12,000 jobs.
‘In 12 months, the Metropolitan Redevelopment Authority has approved more than 170 planning applications for the Armadale and Wungong redevelopment areas,’ he said.
‘This means 150 families have progressed with building their new homes in Wungong, Champion Lakes and Seville Grove and more than 20 new businesses are establishing themselves in Forrestdale Business Park.’
The factory will be ready in 2015.