An electromagnetic-induction-type position detector which detects a position by using electromagnetic induction, comprising: a primary-side plate member including a primary-side main pattern (13,14) and a primary-side sub-pattern (15,16) each of which is formed of a planar coil pattern with comb-shaped poles arranged at a pitch different from that of the other pattern; a secondary-side plate member including a secondary-side main pattern and a secondary-side sub-pattern which are formed of planar coil patterns with comb-shaped poles arranged at different pitches, the secondary-side main pattern and the secondary-side sub-pattern formed in a loop by connecting each adjacent pair of the comb-shaped poles of the secondary-side main pattern and the secondary-side sub-pattern to each other; and a control unit configured to control switching of the primary-side main pattern (13,14) and the primary-side sub-pattern (15,16) to supply an excitation current to one of the primary-side main pattern (13,14) and the primary-side sub-pattern (15,16) and detect an excitation voltage flowing in the secondary-side main pattern or the secondary-side sub-pattern, from the other one of the primary-side main pattern (13,14) and the primary-side sub-pattern (15,16), wherein the primary-side plate member and the secondary-side plate member are arranged to be opposed to each other such that the primary-side main pattern (13,14) and the primary-side sub-pattern (15,16) face the secondary-side main pattern and the secondary-side sub-pattern, respectively, and when the excitation current is supplied to the primary-side main pattern (13,14), the control unit detects the excitation voltage of the secondary-side main pattern excited by the excitation current of the primary-side main pattern (13,14), via the secondary-side sub-pattern by using the primary-side sub-pattern (15,16), and when the excitation current is supplied to the primary-side sub-pattern (15,16), the control unit detects the excitation voltage of the secondary-side sub-pattern excited by the excitation current of the primary-side sub-pattern (15,16), via the secondary-side main pattern by using the primary-side main pattern (13,14). a primary-side plate member including a primary-side main pattern (13,14) and a primary-side sub-pattern (15,16) each of which is formed of a planar coil pattern with comb-shaped poles arranged at a pitch different from that of the other pattern; a secondary-side plate member including a secondary-side main pattern and a secondary-side sub-pattern which are formed of planar coil patterns with comb-shaped poles arranged at different pitches, the secondary-side main pattern and the secondary-side sub-pattern formed in a loop by connecting each adjacent pair of the comb-shaped poles of the secondary-side main pattern and the secondary-side sub-pattern to each other; and a control unit configured to control switching of the primary-side main pattern (13,14) and the primary-side sub-pattern (15,16) to supply an excitation current to one of the primary-side main pattern (13,14) and the primary-side sub-pattern (15,16) and detect an excitation voltage flowing in the secondary-side main pattern or the secondary-side sub-pattern, from the other one of the primary-side main pattern (13,14) and the primary-side sub-pattern (15,16), wherein the primary-side plate member and the secondary-side plate member are arranged to be opposed to each other such that the primary-side main pattern (13,14) and the primary-side sub-pattern (15,16) face the secondary-side main pattern and the secondary-side sub-pattern, respectively, and when the excitation current is supplied to the primary-side main pattern (13,14), the control unit detects the excitation voltage of the secondary-side main pattern excited by the excitation current of the primary-side main pattern (13,14), via the secondary-side sub-pattern by using the primary-side sub-pattern (15,16), and when the excitation current is supplied to the primary-side sub-pattern (15,16), the control unit detects the excitation voltage of the secondary-side sub-pattern excited by the excitation current of the primary-side sub-pattern (15,16), via the secondary-side main pattern by using the primary-side main pattern (13,14).