To provide an aqueous ink composition which contains a self- dispersible colored organic pigment, does not cause blur or offset in recording on plain paper, is excellent in resistances to water, light, and rubbing, and enables high-color-density high-quality (high-definition high-chroma) recording; and a recording apparatus capable of both-sides simultaneous printing.

This ink composition contains a self-dispersible colored organic pigment prepared by modifying a crystalline colored organic pigment by a chemical treatment and/or a physical treatment. The maximum peak of spectral absorption wavelength in the ultraviolet/visible ray absorption spectrum of the crystalline colored organic pigment is shifted to the short wavelength side by the modification. The self-dispersible colored organic pigment has such pseudo-unidimensional crystallization properties that, in the X-ray diffraction spectrum, a diffraction ray exhibiting the maximum strength and its n-th order (n is an integer of 2 or higher) diffraction rays are the main peaks.