The French CAC 40 index was up 0.34 percent or 11.55 points to 3417.34. Shares of Peugeot SA advanced 1.20 percent and those of Danone SA rose 0.81 percent.
London's FTSE 100 index rose 0.30 percent or 17.04 points to 5674.90. Shares of Whitbread PLC climbed 4.24 percent and shares of Evraz PLC advanced 2.08 percent.
The German DAX 30 index rose 0.22 percent or 14.98 points to 6979.67. Shares of Linde AG advanced 1.22 percent and those of Deutsche Bank AG climbed 1.19 percent.
Spain's IBEX 35 was up 0.71 percent or 53.30 points to 7547.30. Shares of Bankia SA rose 2.66 percent and those of Mapfre SA advanced 1.77 percent.
Market players are waiting for an announcement of the stimulus measures by the ECB at its meeting in Frankfurt Thursday, 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.
"Indeed, we expect the Governing Council to announce a new program of conditional government bond purchases with the view of improving the efficiency of its interventions compared with previous SMP versions," Credit Agricole said in a note.
Market players will be disappointed if the ECB decides that the bond purchases will be limited and that the bank will not begin it until the European Financial Stabilization Mechanism (EFSM) or the European Stability Mechanism buy the bonds.
At the same time, it is likely that the central bank will reiterate that the governments must apply to the EFSF for support and accept the conditions set out by the EFSF before the ECB will buy the bonds.