An interdigitated microelectrode biosensor comprising: an insulating layer adapted to cover all of a biosensor formation region of a substrate; a first interdigitated microelectrode having a plurality of first protrusion electrodes arranged in a comb-like shape on the insulating layer of the substrate; a second interdigitated microelectrode facing the first interdigitated microelectrode and having a plurality of second protrusion electrodes arranged in a comb-like shape on the substrate in such a manner as to be interdigitated with the first protrusion electrodes of the first interdigitated microelectrode; a plurality of receptors arranged in the space between the first interdigitated microelectrode and the second interdigitated microelectrode arranged interdigitatedly with each other so as to react specifically with target biomaterials; a protection cap adapted to cover the insulating layer, the first interdigitated microelectrode, and the second interdigitated microelectrode; a polydimethylsiloxane, PDMS, chip attached to prevent non-specific binding to other materials except beta-amyloids and having two microchannels; and an absorption prevention layer, bovine serum albumin, coated on the inner wall of the protection cap and the surfaces of the first interdigitated microelectrode and the second interdigitated microelectrode except the portion where the receptors are not immobilized, wherein the first and second interdigitated microelectrodes are configured such that resistance and reactance between the first interdigitated microelectrode and the second interdigitated microelectrode increase in response to the target biomaterials binding specifically to the plurality of receptors. an insulating layer adapted to cover all of a biosensor formation region of a substrate; a first interdigitated microelectrode having a plurality of first protrusion electrodes arranged in a comb-like shape on the insulating layer of the substrate; a second interdigitated microelectrode facing the first interdigitated microelectrode and having a plurality of second protrusion electrodes arranged in a comb-like shape on the substrate in such a manner as to be interdigitated with the first protrusion electrodes of the first interdigitated microelectrode; a plurality of receptors arranged in the space between the first interdigitated microelectrode and the second interdigitated microelectrode arranged interdigitatedly with each other so as to react specifically with target biomaterials; a protection cap adapted to cover the insulating layer, the first interdigitated microelectrode, and the second interdigitated microelectrode; a polydimethylsiloxane, PDMS, chip attached to prevent non-specific binding to other materials except beta-amyloids and having two microchannels; and an absorption prevention layer, bovine serum albumin, coated on the inner wall of the protection cap and the surfaces of the first interdigitated microelectrode and the second interdigitated microelectrode except the portion where the receptors are not immobilized, wherein the first and second interdigitated microelectrodes are configured such that resistance and reactance between the first interdigitated microelectrode and the second interdigitated microelectrode increase in response to the target biomaterials binding specifically to the plurality of receptors.