The French CAC 40 index was up 0.23 percent or 7.65 point to 3406.69. Shares of Legrand SA advanced 1.61 percent and those of Sanofi rose 0.50 percent.
London's FTSE 100 index marginally dropped 0.04 percent or 2.10 points to 5669.91. Shares of BP PLC fell 3.01 percent and those of BHP Billiton Plc declined 2.05 percent.
The German DAX 30 index rose 0.25 percent or 17.53 points to 6950.11. Shares of SAP AG advanced 1.36 percent and shares of Adidas AG climbed 0.51 percent.
Spain's IBEX 35 was up 0.26 percent or 19.40 points to 7507.60. Shares of Iberdrola SA rose 1.09 percent and those of Abengoa SA advanced 0.90 percent.
Investors will be focusing on the ECB meeting in Frankfurt Thursday. Market players are waiting for an announcement of the stimulus measures by the ECB as investors feel that bold measures, including easing in the monetary policy, will give the much-needed thrust to boost liquidity in the euro zone financial system.
"News headlines coming out of Europe continue to feed market expectation of a major policy announcement by the ECB. Scope for a potential disappointment remains significant, albeit not as damaging to the EUR as once thought. Verbal commitment to preserving the EUR has also helped," Credit Agricole said in a note.
The ECB has so far purchased no additional bonds and its Securities Markets Program has been dormant for five months. But hopes that the ECB is about to restart purchasing peripheral government bonds are growing among investors.