A decentered type contact lens including: an optical zone provided in a center part of the contact lens ; a peripheral zone provided on an outer circumference of the optical zone ; an optical center of the optical zone being set to deviate from a lens geometric center ; and a circumferential direction alignment mechanism for setting a lens circumferential direction position in a worn state, the contact lens being characterized in that : a center-of-gravity deviation in relation to the lens geometric center is set for the peripheral zone , and a center-of-gravity position shift accompanying deviation of the optical center of the optical zone in relation to the lens geometric center is corrected by offset using the center-of-gravity deviation of the peripheral zone , and when the optical zone has plus diopter correction optical characteristics with the optical center being set with the deviation from the lens geometric center , the center-of-gravity deviation provided at the peripheral zone is set in relation to the lens geometric center so that a lens center-of-gravity position is made to deviate to a side opposite an optical center deviation direction, while when the optical zone has minus diopter correction optical characteristics with the optical center being set with the deviation from the lens geometric center , the center-of-gravity deviation provided at the peripheral zone is set in relation to the lens geometric center so that a lens center-of-gravity position is made to deviate to the same side as an optical center deviation direction, and the circumferential direction alignment mechanism is constituted by providing on the peripheral zone a pair of thin parts positioned vertically and a pair of thick parts positioned laterally, and the center-of-gravity deviation in relation to the lens geometric center is set by making a thickness dimension of one thick part of the pair of thick parts to be larger than another thick part of the pair of thick parts . a center-of-gravity deviation in relation to the lens geometric center is set for the peripheral zone , and a center-of-gravity position shift accompanying deviation of the optical center of the optical zone in relation to the lens geometric center is corrected by offset using the center-of-gravity deviation of the peripheral zone , and when the optical zone has plus diopter correction optical characteristics with the optical center being set with the deviation from the lens geometric center , the center-of-gravity deviation provided at the peripheral zone is set in relation to the lens geometric center so that a lens center-of-gravity position is made to deviate to a side opposite an optical center deviation direction, while when the optical zone has minus diopter correction optical characteristics with the optical center being set with the deviation from the lens geometric center , the center-of-gravity deviation provided at the peripheral zone is set in relation to the lens geometric center so that a lens center-of-gravity position is made to deviate to the same side as an optical center deviation direction, and the circumferential direction alignment mechanism is constituted by providing on the peripheral zone a pair of thin parts positioned vertically and a pair of thick parts positioned laterally, and the center-of-gravity deviation in relation to the lens geometric center is set by making a thickness dimension of one thick part of the pair of thick parts to be larger than another thick part of the pair of thick parts . <EOS>