There is provided a wide-band direct conversion transmitting apparatus including: a local oscillation unit generating first, second, and third oscillation signal pairs each including a pair of signals having a phase difference of 90°; an image rejection mixer unit mixing baseband transmission signals including an I signal and a Q signal having a phase difference of 90° with the first oscillation signal pair; a harmonic rejection mixer unit mixing each of the first, second, and third oscillation signal pairs with the baseband transmission signals; and an output signal selecting unit selecting output signals from the image rejection mixer unit or from the harmonic rejection mixer unit.