The average price paid by marketers for cost-per-click (CPC) ads dropped 8% in the quarter, as users migrated from the desktop to mobile platforms, which are seen as less valuable by advertisers than larger screens.
Google says the decline in CPC rates was due to changes in its advertising formats, which has driven the sharp increase in the total number of clicks by users, which is up 34% year on year.
The search giant reported a 27% increase in revenue to $10.6bn.