Giroud has enjoyed a fine start to the campaign, scoring five goals in all competitions, including the opener in Arsenal's first four Premier League games.
Wenger believes that the French international is approaching his peak years and has all the attributes to excel at the Emirates for a prolonged spell.
He told The Mirror: "Giroud is already [one of the leading strikers in Europe]. I think will he improve and be better in all the aspects of his game. As long as all the aspects are there, the attitude is there as well.
"At 27, you always think the best years are coming for him now. I am never surprised by the improvement of the players, because that gives you the feeling that we are doing the right things.
"For him, the jump from Montpellier to Arsenal was quite big. In the first season, it is always quite difficult."