Sense lines in a self-capacitance touch panel are multiplexed. A touch panel controller (3) includes a drive circuit (4) that drives drive lines (D0 through D(K−1)), based on a drive code series, a code multiplication unit (11) that reads multiple linear sum signals along the sense lines (S0 through S(M−1)), based on the charges of detection electrodes (E) and performs an inner product computation with a detection code series, and a detection circuit (6) that detects a capacitance or a change in the capacitance.