Judging from our experience these past 30-40 years of visiting civil engineering heritage and industrial heritage, including ruins, we saw many things which were interesting, unforgettable, familiar or enlightening, though they were not then included in the category of today's cultural assets. We did not investigate them too much because they were not considered cultural assets, but they were the things about which we wanted to tell others. Therefore, we began to pay more attention to such assets based on discussions during field work. We decided to name it "geek heritage". "Geek" is not a Japanese word, but an English word. An English dictionary says that it is slang used in the United States and that it means an " entertainer performing a grotesque show" (e.g. someone who chews and tears off the head of a live chicken) or an eccentric, an unpleasant person, and even a serious student. We also found that an example of an eccentric is an expression “computer geek”. ("Random House" electronic dictionary version) If we go by this definition, "geek heritage" would be "a heritage that an eccentric person likes". If we define the meaning of a geek to be "a serious student", it would be a heritage which a serious person or an earnest person likes. However, the words change. Recently in the United States, they started to use “geek” in a good way, meaning a person having geek knowledge is someone with deep knowledge and “Otaku” in Japanese (in a good way). Instead of using such an English word, “geek”, we could use a Japanese word such as Class B heritage, Getemono heritage, a limited heritage and a gonzo heritage, but we decided to use “Geek Heritage” anyway considering a promotional point of view, as well as its newness and smartness. The key point is to make the term international. 　　　In this paper, we propose a new heritage concept of “Geek Heritage” and explain both past and present examples.