1931年9月18日,日本悍然发动了对中国东北的进攻,很快占领了东北全境。继而在1937年7月一手制造卢沟桥事变,从而点燃了全面侵华战争的战火。然而非常奇怪的是,自1931年“九·一八”到1945年日本战败投降的长达14年的武装侵华过程中,日本却始终没有向中国正式宣战。这是一个值得注意的现象。本文拟对日本不向中国宣战的原因作一粗浅的分析和探讨。 On September 18, 1931, Japan brazenly launched an offensive on northeast China and quickly occupied the entire northeastern region. Then, in July 1937, the Lugouqiao incident was first fabricated, thus igniting the war on an all-outwar to China. However, it is very strange that during the 14-year armed invasion that Japan surrendered in Japan from September 18 to September 1945, Japan did not officially declare war on China. This is a noteworthy phenomenon. This article intends to make a superficial analysis and discussion on the reasons why Japan did not declare war on China.