Provided are a signal detection device and method, said device comprising: a fixing band (1) and a differential amplifier circuit (3), the inner side of said fixing band (1) being provided with a plurality of electrode plates (2) there is at least one electrode plate among said plurality of electrode plates that serves as an emitting electrode plate there are at least two electrode plates among said plurality of electrode plates that serve as two receiving electrode plates, and the two receiving electrode plates are respectively connected to the two input terminals of said differential amplifier circuit (3) all of the electrode plates are disposed on the inner side of the fixing band (1), and the shape of the distribution of the electrode plates (2) on said fixing band matches the shape of at least one cranial suture on the skull of the test subject. When the device is used for detecting conditions inside the brain, if the positions of the electrode plates (2) on the inner side of the fixing band (1) match the position of a cranial suture on the brain, then the received electromagnetic wave signal is clearer then, by means of differential amplifier circuit processing, the interference signal loaded to the electrode plates is eliminated, thus the conditions inside the brain are reflected more accurately.Linvention concerne un dispositif et un procédé de détection de signal, ledit dispositif comprenant : une bande de fixation (1) et un circuit amplificateur différentiel (3), le côté interne de ladite bande de fixation (1) étant muni dune pluralité de plaques délectrode (2) au moins une plaque délectrode parmi ladite pluralité de plaques délectrode servant en tant que plaque délectrode démission au moins deux plaques délectrode parmi ladite pluralité de plaques délectrode servant en tant que deux plaques délectrode de réception, et les deux plaques délectrode de réception sont respectivement connectées aux deux bornes dentrée dudit circuit amplificateur différentiel
