Cell-phone, including smart-phone, is one of the leading candidates of convenient medium for reading e-books. However, it is unknown if cell-phones are really as readable as conventional paper books. We are focusing on differences in performance of readings with a traditional paper book and a latest cell-phone. Comprehension, absorption, and required period were measured after completion of reading a novel by each subject who used paper book or cell-phone, respectively. Differences of the measured results on the two different medium are analyzed and discussed.