Masabumi Hosono (細野 正文, Hosono Masabumi; 15 October 1870 – 14 March 1939) was a Japanese civil servant. He survived the sinking of the Titanic on 15 April 1912 but found himself condemned and ostracized by the Japanese public, press, and government because of a misconception that he decided to save himself rather than go down with the ship. Hosono's grandson is Haruomi Hosono, leading member of the Japanese band Yellow Magic Orchestra.

Masabumi Hosono was born on 15 October 1870, in the village of Hokura, now part of the city of Jōetsu, in Niigata Prefecture. In 1896, he graduated from the Tokyo Higher Commercial School (now Hitotsubashi University) and joined the Mitsubishi Joint Stock Company. In 1897, he left the company to work as a cargo clerk at the Shiodome Freight Terminal in Tokyo. In 1906, he completed a Russian language course at the Tokyo Language School (now the Tokyo University of Foreign Studies), and became a manager in the Accounting and Investigating Division of the Imperial Railroad Office the following year. In 1908, he became a railroad director.^{[citation needed]}

In 1910, Hosono, working for the Ministry of Transport, was sent to Russia to research the Russian state railway system. His journey back to Japan took him first to London, where he stayed for a short time, then to Southampton where he boarded Titanic on 10 April 1912 as a second class passenger.

During the night of 14/15 April he was awakened by a steward. However, he was blocked from going to Titanic's boat deck, from which lifeboats were already being launched, as a crewman assumed that he was a third class passenger. He eventually made his way past the obstruction and made his way to the boat deck, where he saw with alarm that emergency flares were being fired: "All the while flares signalling emergency were being shot into the air ceaselessly, and hideous blue flashes and noises were simply terrifying. Somehow I could in no way dispel the feeling of utter dread and desolation."

Hosono saw four lifeboats being launched and contemplated the prospect of an imminent death. He was "deep in desolate thought that I would no more be able to see my beloved wife and children, since there was no alternative for me than to share the same destiny as the Titanic". As the number of lifeboats remaining diminished rapidly, "I tried to prepare myself for the last moment with no agitation, making up my mind not to leave anything disgraceful as a Japanese subject. But still I found myself looking for and waiting for any possible chance for survival."

沈ミシ後ニハ溺死セントシツツアル人々ノ叫声実ニモノスゴク、ボート内ニハ其夫父等ヲ案ジツツアル婦人連ノ泣ク声亦盛ニテ嗚呼自分モ何ウナルコトカト思フ時ハ気モ心モ沈ミシ心地ナリシ 。

After the ship sank there came back again frightful shrills and cries of those drowning in the water. Our lifeboat too was filled with sobbing, weeping children and women worried about the safety of their husbands and fathers. And I, too, was as much depressed and miserable as they were, not knowing what would become of myself in the long run.

At about 8 am on 15 April, the lifeboat's passengers were rescued by the RMS Carpathia. Once aboard, Hosono slept in the smoking room but avoided it when he could as he was the target of jokes by the seamen, whom he called "a good-for-nothing band of seamen" for whom "anything I say falls on deaf ears." He pushed back, showing them "a bulldog tenacity" and eventually gained what he called "a bit of respect". He still had in his coat pockets a sheaf of stationery with Titanic's letterhead on which he had started writing a letter to his wife in English. During Carpathia's voyage to New York, he used the paper to write an account in Japanese of his experiences. It is the only such document known to exist on Titanic stationery.