A signal detecting apparatus, comprising: a plurality of electrodes, configured to engage the object to generate a signal; selecting unit, based on the selection signal, a selection signal on said selected plurality of electrodes; amplifying unit, its selected by the selection signal amplifying section; and a matrix, which is formed of the plurality of electrodes, and said selection section and the amplification section have flexibility, the amplifying portion with said plurality of electrodes and the said selection portion has a multilayer structure formed on said substrate.