Roethlisberger hooked up with Will Johnson and Jerricho Cotchery for scoring strikes in the final quarter as the Steelers (4-6) won a second straight.
The Pittsburgh quarterback went 29-for-45 through the air for 367 yards.
Antonio Brown led the Steelers' receiving corps with seven catches for 147 yards and two scores.
The Lions (6-4) had their two-game winning streak snapped despite a good performance from Matthew Stafford, who completed 19-for-46 passes for 362 yards, two touchdowns to Calvin Johnson and one interception.
Johnson finished with six grabs for 179 yards.