We demonstrate the optical near-field enhancement of a metal-aperture GaAs VCSEL with a nanometer-size Au particle. We achieved a record near-field intensity estimated from far-field measurements. The far-field output power from the nano-aperture was increased by a factor of 1.8 by inserting an Au nano-particle. The optical near-field was localized with a near-field power density of 5.7mW/µm² and a spot size of 280nm. Also, we could avoid the polarization dependence of metal-aperture VCSELs by using a symmetric-shaped nano-particle in a metal aperture. This significant improvement may enable us to use the nano-aperture VCSEL for high-density optical storages.