A pointer detection apparatus for detecting a pointer positioned on a conductor pattern, the conductor pattern including a plurality of first conductors disposed in a first direction and a plurality of second conductors disposed in a second direction which crosses the first direction, the pointer detection apparatus comprising: a code supplying circuit configured to supply a plurality of code strings (C 1, C 2,..., C k) of different codes, the code supplying circuit being configured to supply predetermined ones of the code strings (C 2, C 3,..., C k) to the first conductors disposed in the first direction; a correlation value calculation code supplying circuit (34c k) configured to supply correlation value calculation codes (C' 1, C' 2,..., C' k) respectively corresponding to the code strings (C 1, C 2,..., C k); wherein the code strings (C 1, C 2,..., C k) are constructed from a Hadamard matrix and are mutually orthogonal to each other, and characterized in that the pointer detection apparatus includes a correlation calculation circuit configured to carry out correlation calculation between signals (PS k) produced in the second conductors disposed in the second direction and the correlation value calculation codes (C' k) to determine first correlation calculation values and to carry out correlation calculation with a correlation value calculation code (C 1 ') of a further code (C 1) of the code strings (C 1, C 2,..., C k) to determine a further correlation calculation value, the code supplying circuit is connected to an amplification circuit of the pointer detection apparatus and is configured to supply the further code (C 1) of the code strings (C 1, C 2,..., C k) to said amplification circuit and not to the first conductors, so as not subject said further code (C 1) of the code strings (C 1, C 2,..., C k) to a variation factor introduced by the first conductors and the second conductors, and the pointer detection apparatus includes a position detection circuit adapted to detect the pointer positioned on said conductor pattern based on the first correlation calculation values and the further correlation calculation value obtained by said correlation calculation circuit, wherein said further code (C 1) of the code strings (C 1, C 2,..., C k) is used as a calibration signal for the correlation calculation by the correlation calculation circuit. a code supplying circuit configured to supply a plurality of code strings (C 1, C 2,..., C k) of different codes, the code supplying circuit being configured to supply predetermined ones of the code strings (C 2, C 3,..., C k) to the first conductors disposed in the first direction; a correlation value calculation code supplying circuit (34c k) configured to supply correlation value calculation codes (C' 1, C' 2,..., C' k) respectively corresponding to the code strings (C 1, C 2,..., C k); wherein the code strings (C 1, C 2,..., C k) are constructed from a Hadamard matrix and are mutually orthogonal to each other, and characterized in that the pointer detection apparatus includes a correlation calculation circuit configured to carry out correlation calculation between signals (PS k) produced in the second conductors disposed in the second direction and the correlation value calculation codes (C' k) to determine first correlation calculation values and to carry out correlation calculation with a correlation value calculation code (C 1 ') of a further code (C 1) of the code strings (C 1, C 2,..., C k) to determine a further correlation calculation value, the code supplying circuit is connected to an amplification circuit of the pointer detection apparatus and is configured to supply the further code (C 1) of the code strings (C 1, C 2,..., C k) to said amplification circuit and not to the first conductors, so as not subject said further code (C 1) of the code strings (C 1, C 2,..., C k) to a variation factor introduced by the first conductors and the second conductors, and the pointer detection apparatus includes a position detection circuit adapted to detect the pointer positioned on said conductor pattern based on the first correlation calculation values and the further correlation calculation value obtained by said correlation calculation circuit, wherein said further code (C 1) of the code strings (C 1, C 2,..., C k) is used as a calibration signal for the correlation calculation by the correlation calculation circuit.