The European Commission released its economic sentiment index for the Eurozone on Tuesday. The index increased to 105.6 in September from 104.1 in August. It was the highest level since April 2011.
August's figure was revised down from 104.2.
Analysts had expected the index to remain unchanged at 104.1.
The increase was driven by improvements in the industry, services and retail trade sectors.
The industrial confidence index increased to -2.2 in September from -3.7 in August, beating expectations for a decline to -3.8.
The final consumer confidence index was down to -7.1 in September from -6.9 in August, in line with expectations.
The business climate index climbed to 0.34 in September from 0.2 in August. Analysts had expected the index to remain unchanged at 0.2.