The present disclosure provides a sheet-form electrode for a secondary battery, comprising a current collector; an electrode active material layer formed on one surface of the current collector; a conductive layer formed on the electrode active material layer and comprising a conductive material and a binder; and a first porous supporting layer formed on the conductive layer. The sheet-form electrode for a secondary battery according to the present disclosure has supporting layers on at least one surfaces thereof to exhibit surprisingly improved flexibility and prevent the release of the electrode active material layer from a current collector even if intense external forces are applied to the electrode, thereby preventing the decrease of battery capacity and improving the cycle life characteristic of the battery.