  We present the result of searching for clusters of galaxies based on weak
gravitational lensing analysis of the $\sim 160$~deg$^2$ area surveyed by Hyper
Suprime-Cam (HSC) as a Subaru Strategic Program. HSC is a new prime focus
optical imager with a 1.5 diameter field of view on the 8.2-meter Subaru
telescope. The superb median seeing on the HSC $i$-band images of $0.56$ arcsec
allows the reconstruction of high angular resolution mass maps via weak
lensing, which is crucial for the weak lensing cluster search. We identify 65
mass map peaks with signal-to-noise (SN) ratio larger than 4.7, and carefully
examine their properties by cross-matching the clusters with optical and X-ray
cluster catalogs. We find that all the 39 peaks with SN$>5.1$ have counterparts
in the optical cluster catalogs, and only 2 out of the 65 peaks are probably
false positives. The upper limits of X-ray luminosities from ROSAT All Sky
Survey (RASS) imply the existence of an X-ray under-luminous cluster
population. We show that the X-rays from the shear selected clusters can be
statistically detected by stacking the RASS images. The inferred average X-ray
luminosity is about half that of the X-ray selected clusters of the same mass.
The radial profile of the dark matter distribution derived from the stacking
analysis is well modeled by the Navarro-Frenk-White profile with a small
concentration parameter value of $c_{500}\sim 2.5$, which suggests that the
selection bias on the orientation or the internal structure for our shear
selected cluster sample is not strong.
