To provide an anode, corrosion-protecting structure of a concrete constructions using this, and a corrosion protection method capable of protecting electrical corrosion, with little generation of gas due to electrolysis of water or chlorine compounds, by decreasing as far as possible the amount of processing performed on the structural body in on-site construction work and suppressing the voltage that is conducted therethrough to a low level. [Solution] A corrosion-protecting structure (1) is constituted by attaching an anode (10) to the surface layer (3) of a corrosion-protecting body (4) through a first electrolyte layer (12) on one face of a conductive layer (11) formed as a sheet. The electrolyte is formed as a sheet. The first electrolyte layer (12) having adhesiveness is attached to the conductive layer (11) and the surface layer (3) of the corrosion-protecting body (4).