In 1895, Taiwan was incorporated into Japan as its first colony. A lot of Japanese, including administrators, soldiers, teachers, policemen, and general citizens came to Taiwan. At that time, the Japanese arrivals came into contact with the various languages of Taiwan, and realized that Taiwanese 台湾語 was the most important language in Taiwan for administration, military operation, education, and commerce, etc. Japanese teachers and policemen were required to acquire some Taiwanese language skills, and were able to receive such education at a few government-owned language schools. However, soldiers and general citizens had almost no chance to learn Taiwanese at a formal language school.. The army needed to communicate with the locals in Taiwanese languages for military operations. The army demanded that some soldiers acquire limited Taiwanese language abilities, and training of the special interpreters was also strongly needed. In particular, military police came into direct contact with the locals, and so it was extremely important that they were able to speak Taiwanese. Then, the military quickly prepared many language teaching materials and language teachers. Accordingly, these Taiwanese textbooks now serve as good research materials to better understand the real situation of Taiwanese languages 120 years ago. The Japanese general citizens who traveled to Taiwan in those days did not have a deep understanding of the Taiwanese language. Therefore, the descriptions concerning Taiwanese language in their travel records is very superficial and confused. Nevertheless, they, too, constitute good data to examine Taiwanese language recognition at that time. This paper aims to discuss how the Japanese perceived the language of Taiwan through the investigation of a lot of travel records to Taiwan and Taiwanese textbooks published in the early stages of the Japanese colonial period, i.e.水野遵《台灣征蕃記》A Record of Savage Conquest, 福島安正《淡水新政記》A Record of New Government in Tansui, 秋山啓之《實用日台新語集》Practical New Language of Japanese and Taiwanese, 姬田良造《台灣土語入門》Introduction to Taiwan Native Language, 俣野和吉《軍人用台灣語》Taiwanese for Soldiers, etc.