The two clubs agreed an undisclosed fee for the 28-year-old, who has passed a medical and will provide competition for Gary Montgomery in the Millers goal.
"It's been difficult at Stockport following relegation and several players leaving the club," Cutler told the Millers' website.
"So it's nice to be with a big club again, and last season's relegation hasn't put me off Rotherham at all."