The 165MW project, being developed by Sumitomo Corporation Europe, Parkwind and Meewind, secured €460m in financing.
European Investment Bank will offer €250m in loan for the project which will be enough to provide around 38% of the total project cost.
EIB vice-president Pim van Ballekom said: "Since 2009 the EIB has invested more than EUR1bn in wind energy projects in Belgium to ensure a safe, affordable and diversified supply for a large portion of the Belgian population.
"Fighting climate change is a long-term goal for the EIB and we hope to see more projects like this one in Belgium in the coming years."
Located in the North Sea, around 45km to the north of the Belgian coast, the project will consist of 50 units of MHI Vestas-built 3.3MW wind turbine generators.
Upon completion in 2017, the wind facility is expected to generate clean energy that will be enough to power around 186,000 households.
A Belgian utility will purchase the electricity from the project, under a long-term power purchase agreement.
Sumitomo said: "The project marks the first time a Japanese corporation has joined an off-shore wind farm project company in Europe at the early development stage.
"By leveraging the experience and know-how gained through the Project, Sumitomo aims to continue development of off-shore wind farms in Europe and contribute to global sustainability."
