We are carrying out a wide-area imaging survey with the Subaru Hyper Suprime-Cam (HSC), starting from 2014 for 6 years. Thanks to the photon correcting power, wide-field capability and superb image quality, the HSC images allow for a high precision measurement of weak lensing distortion effects on images of distant galaxies, which in turn enables us to infer the spatial distribution of matter (mostly dark matter) over cosmic time. Here we will present the first HSC cosmological constraints. Then if time allows, I will describe details of the Prime Focus Spectrograph (PFS), which is under construction and will carry out a wide-area spectroscopic observation of HSC stars/galaxies.