There is disclosed a showerhead apparatus for radical-assisted deposition including a showerhead of a two-stair structure separated by a given distance, which has a first buffer for uniformly distributing a raw material gas and a second buffer for uniformly distributing a plasma gas, wherein a plasma is generated within the showerheads and the raw material gas sprayed into the plasma is constantly maintained, thus forming a uniform thin film on a wafer or a substrate. The showerhead apparatus for radical-assisted deposition comprises a raw material gas spray mechanism including a first buffer which is divided into upper and lower layers for uniformly distributing a gas introduced from a raw material gas injection tube, wherein a plurality of raw material gas spray holes for spraying the raw material gas distributed within the first buffer at a given flow rate is formed at a lower plate of the spray mechanism; a plasma generating gas spray mechanism including a second buffer for uniformly distributing a plasma generating gas between with the raw material gas spray mechanism, wherein a plurality of plasma generating gas spray holes and through holes for spraying the plasma generating gas distributed within the second buffer are formed at a lower plate of the spray mechanism, respectively; a guide mechanism for communicating the raw material gas spray holes in the raw material gas spray mechanism and the through holes in the plasma generating gas spray mechanism and for inducing the raw material gas and the plasma generating gas so that they are not mixed; and a RF generating mechanism mounted at one outside side of the raw material gas spray mechanism, wherein a RF rod for applying an outside RF power is included at a lower plate of the RF generating mechanism.