Ronaldo scored a club record 42 goals for United last season, but Rooney has already scored 32 goals this season.
Rooney scored two in the 3-0 win over Fulham on Sunday.
“It’s not something I’ve looked at if I’m honest,” Rooney told Sky Sports.
“Obviously I want to score goals in every game.
“What Cristiano achieved was unbelievable. But I’m a different person and I wouldn’t compare myself to him.”