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; and a first porous supporting layer formed on the electrode active material layer. The sheet-form electrode for a secondary battery according to the present disclosure has supporting layers on at least one surface 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. Also, the sheet-form electrode has a porous supporting layer to allow good introduction of an electrolyte solution in an electrode active material layer, and also the electrolyte solution can be impregnated into the pores of the porous supporting layer to inhibit a resistance rise in the battery, thereby preventing the deterioration of battery performances.