We have developed a visible imager and spectrograph, Nayoro Optical Camera and Spectrograph (NaCS), in- stalled at the f/12 Nasmyth focus of the 1.6-m Pirka telescope of the Hokkaido University in Hokkaido, Japan. The optical and mechanical design is similar to that of WFGS2 of the University of Hawaii 2.2-m telescope (UH88), however the camera is newly designed. The spectral coverage is 380–970 nm, and the ﬁeld of view is 8.4 × 4.5 arcmin with a pixel scale of 0.247 arcsec pixel-1. The SDSS (g', r', i', z') ﬁlters, Johnson (B, V ) ﬁlters and a replica grism (R ~300 at 650 nm) are equipped. The slit width can be selected from 2, 3, and 4 arcsec. We selected a 2kx1k fully-depleted back-illuminated Hamamatsu CCD as a detector, because it has a high quantum efficiency (≥ 80 %) over optical wavelength. The Kiso Array Controller (KAC) is used as a CCD controller. The ﬁrst light observation was done on November 2011. NaCS is used mainly for long-term spectroscopic monitor of active galactic nuclei. It is also used for several astronomical observations such as light-curve measurements of asteroids and search of pre-main-sequence stars and brown dwarfs by slit-less spectroscopy as a major facility instrument of the Pirka telescope. We present the design, construction, integration, and performance of this instrument.