"Two employees, including a 14-year-old boy, were killed and 15 others wounded in the overnight air raid," Faisal al-Musaabi said.
A search was underway for another employee still buried under the rubble of the building in the east of Sanaa, the factory owner told AFP.
The coalition has been carrying out air strikes against Iran-backed rebels across Yemen since March.
The rebels, who have controlled Sanaa since September 2014, reported a higher death toll of 11 employees killed and four others wounded in the strike on the workshop, according to their sabanews.Net website.
The coalition last month announced that an independent inquiry would examine charges of possible abuses against civilians in the conflict.
A panel of UN experts says the coalition has carried out 119 sorties that violated humanitarian law, and called for an international probe.