G. Mikhlin proved the boundedness of the Fourier multiplier operator in the classical Lebesgue space if the multiplier function is a bounded function. In [2], the authors obtained the same result of the classical Morrey space. In this paper, we prove that Mikhlin operator with bounded multiplier function is bounded operator on Morrey space with variable exponent which is containing the classical Lebesgue space with variable exponent and the classical Morrey space.