本文探究日治時代中期（自大正13年至昭和7年）由在臺日人所組成的東臺灣研究會，及其所發行97期的東臺灣研究叢書的史料價值。根據本文的整理，結論如下： 日治時代的東臺灣研究會乃日治中期，由日本記者橋本白水所發起、會員以在臺日人為主、並以民間立場提倡東臺灣開發的地方性團體。這個團體主要透過以月刊形式發行的「東臺灣研究叢書」，表達各項在臺日本官民對東臺灣開發的意見，以提供臺灣總督府作為臺灣東部各項建設、及施政的參考為主要目的。 「東臺灣研究叢書」的各項內容，或為官廳報告、或為地方調查研究報告、或為有關地方興革之意見，雖為私人立場所編刊物，其中不乏官方資料，及詳於考據的研究報告，可作為日治時代有關臺灣東部研究的參考資料。

This work investigate the Eastern Taiwan Investigation Association which was composed of Japanese in Taiwan, and the historical valuation of its publication during the mid-era of Japanese Dominance Period. According to the research, the results are as following: The Eastern Taiwan Investigation Association was created by Hakusui Hasimoto whom was a Japanese newsman. The members were mainly composed of Japanese in Taiwan. And they, as a local group, engaged in developing eastern Taiwan in civilian situation. They mainly published the Eastern Taiwan Researching Journal monthly, and reported the ideas of developing eastern Taiwan from the public and the official to offer the Taiwan Government General for constructing eastern Taiwan. The articles of Eastern Taiwan Researching Journal are about the official investigation, the civilian reports, and the ideas of eastern Taiwan development. Though it is a civilian journal, there are a lot of the official materials and precise researches for investigating eastern Taiwan of the Period of the Japanese Dominance.