  We present high resolution H-band polarized intensity (PI; FWHM = 0."1: 14
AU) and L'-band imaging data (FWHM = 0."11: 15 AU) of the circumstellar disk
around the weak-lined T Tauri star PDS 70 in Centaurus at a radial distance of
28 AU (0."2) up to 210 AU (1."5). In both images, a giant inner gap is clearly
resolved for the first time, and the radius of the gap is ~70 AU. Our data show
that the geometric center of the disk shifts by ~6 AU toward the minor axis. We
confirm that the brown dwarf companion candidate to the north of PDS 70 is a
background star based on its proper motion. As a result of SED fitting by Monte
Carlo radiative transfer modeling, we infer the existence of an optically thick
inner disk at a few AU. Combining our observations and modeling, we classify
the disk of PDS 70 as a pre-transitional disk. Furthermore, based on the
analysis of L'-band imaging data, we put an upper limit mass of companions at
~30 to ~50MJ within the gap. Taking account of the presence of the large and
sharp gap, we suggest that the gap could be formed by dynamical interactions of
sub-stellar companions or multiple unseen giant planets in the gap.
