The University of Tokyo Atacama Observatory (TAO) is a project to build a 6.5m telescope at the world highest (5640m) Chajnantor site. TAO has a mid-infrared camera and spectrograph MIMIZUKU as the first generation facility instrument. TAO/MIMIZUKU is a unique instrument and has advantages over existing mid-infrared instruments. 1) Wide wavelength coverage from 2-38 micron. Especially 28-38 micron wavelength range is accessible only from the 5km altitude TAO site. 2) Accurate monitoring capability. MIMIZUKU equips a newly developed opto-mechanical device Field Stacker. It enables simultaneous observations of two or more stars and improves photometric accuracy by realtime calibration of atmospheric transmittance. In this talk I will present details, current status, and schedule of TAO/MIMIZUKU.