The Improved Limb Atmospheric Spectrometer-II (ILAS-II) onboard the Advanced Earth Observing Satellite-II (ADEOS-II) was successfully launched on 14 December, 2002 from Japan Aerospace Exploration Agency (JAXA)'s Tanegashima Space Center. ILAS-II is a solar-occultation atmospheric sensor which measures vertical profiles of O3, HNO3, NO2, N2O, CH4, H2O, ClONO2, aerosol extinction coefficients etc. with four grating spectrometers. After the checkout period of the ILAS-II, ILAS-II started its routine operation since 2 April 2003 until 24 October 2003, when ADEOS-II lost its function due to solar-paddle failure. However, about 7 months of data were acquired by ILAS-II including whole period of Antarctic ozone hole in 2003 when ozone depletion was one of the largest up to now. ILAS-II successfully measured vertical profiles of ozone, nitric acid, nitrous oxide, and aerosol extinction coefficients due to Polar Stratospheric Clouds (PSCs) during this ozone hole period. The ILAS-II data with the latest data retrieval algorithm of Version 1.4 shows fairly good agreement with correlative ozonesonde measurements within 15% accuracy.