We demonstrate the permeabilization of cell membranes by an enhanced optical field generated under polystyrene microspheres of $1000\mathrm{nm}$ diameter excited by a femtosecond laser pulse. Fluorescent molecules and short interfering RNA (siRNA) have been successfully delivered to many cells in the irradiated area by a single $80\mathrm{fs}$ laser pulse at $800\mathrm{nm}$ wavelength in the presence of antibody-conjugated polystyrene spheres. The ratios of the cells showing permeabilization were 38% and 21% for Fluorescein isothiocyanate-dextran and siRNA, respectively, at the laser fluence of $1.06\mathrm{J}/{\mathrm{cm}}^2$ . The present method has advantages both in high throughput of many cell treatments and precise processing of minute areas on cell membranes.