When an ideal value of a width of each of a plurality of detecting electrodes (input-position detecting electrodes) in an X direction provided in an input device is defined as Wsmax [μm], an interval which is a center-to-center distance of adjacent detecting electrodes is defined as P [μm], and an effective inter-electrode distance represented by an inverse number of a value obtained by dividing a relative permittivity of an intermediate member by a thickness of the intermediate member is defined as D [μm], Wsmax is represented by a formula of: Wsmax=0.488×P-4.33×D-160. Also, a width of each of the plurality of detecting electrodes in the X direction falls within a range of not more than ±150 μm of a value of the Wsmax.