Differential Evolution is a competitive optimization technique over continuous space. The operation in the original Differential Evolution is simple, however, the mechanism, in the Differential Evolution makes it practically impossible to effectively use the original Differential Evolution to the binary space. A novel binary mutation operation was defined to enable the Differential Evolution to operate within the binary space. The new binary mutation works well in the binary space without the original scale factor F. Initial experimental results of three different sizes of knapsack problems and the One-Max problem indicate the effectiveness and validity of the binary Differential Evolution operating in binary space.