An apparatus of a Harmonic Rejection Mixer (HRM) for removing a harmonic component and an operating method thereof are provided. The HRM includes a Local Oscillator (LO), at least one frequency converter, at least two mixers, at least one phase converter, and a combiner. The LO generates an LO signal. The at least one frequency converter multiplies the LO signal using different variables to provide the same to at least two mixers. The at least two mixers convert a frequency band of an input signal using the LO signal provided from the LO and the at least one frequency converter. The at least one phase converter controls a phase of an output signal of at least one other mixer excluding one of the at least two mixers. The combiner combines an output signal of the one mixer with an output signal of the at least one phase converter.