My current research focuses on an experimental cosmology. I am working on the Comic Microwave Background (CMB) polarization experiment, POLARBEAR. CMB observations in the last decades have provided us with rich information about our universe. Recently the polarization measurement of CMB has attracted much attention because it is considered as a new probe for the epoch of in¬flation, the exponential expansion of the early universe. We deployed our telescope with polarization sensitive detectors in the Atacama Desert in Chile, and we have been observing CMB since 2012. We aim to measure undetected polarization pattern called“B-mode”and acquire new insight on the beginning of the universe.