Testing is underway on all 3,600 workers at the factory, said the local public health office.
Cal-Comp describes itself as the largest electronics producer in Thailand, manufacturing equipment for export worldwide.
The company said all employees will be paid at the normal rate during the factory closure and quarantine. It said it will also provide meals for quarantined workers.
Thailand logged 3,481 new Covid-19 cases and 32 deaths on Friday.