日本的平均初婚年齡於1950年男性為25.9歲、女性23歲。但於2010年時，男性則提高至30.5歲、女性28.8歲。隨著平均初婚年齡提高，日本的未婚率也隨之上升。在2010年度時25歲至29歲的男性未婚率約為70%、女性未婚率約為60%，可想而知，晚婚、未婚化現象的問題已日益嚴重。 本文係針對與父母同居的所謂『單身寄生族』的未婚族群，來分析日本晚婚、未婚化現象的原因。根據國立社會保障－人口問題研究所所發表數據統計，日本未婚者與父母同居比例大約佔七成左右的極高比重，而如此高的數據，可說是日本的特徵。 因此，若以海外傳統的、以獨居單身者結婚為前提而分析出的結婚理論，用來分析探究本文所述日本的晚婚、未婚化的原因，是有困難的。 為了解決像日本相同有著高比率未婚者與父母同居的國家之晚婚、未婚化問題，有必要詳查未婚者與父母同居現狀、發生要因等，以找出解決問題的方法。 In 1950, the average age at first marriage of male was 25.9 and that of female was 23 in Japan, which rose to 30.5 and 28.8 respectively in 2010. Along with the increase of the average age at first marriage is the rise of the rate of non-marriage in 2010 which was 70% for male at the age of 25 to 29 and 60% for female at the same age, signifying the worsening situation of late marriage or non-marriage. This study makes an analysis of the reasons why the phenomena of late marriage and non-marriage happened to parasite single in Japan. A data statistics published by National Institute of Population and Social Security Research shows that as high as 70% of the singles live with their parents, which virtually becomes a symbol of Japan. Thus, it’s difficult to figure out the reasons for the phenomena of late marriage and non-marriage in Japan by adopting the marriage theory based on the conditions of traditional foreign singles that live alone. In order to find a solution to the problems of late marriage and non-marriage in the nations with high non-marriage rate, such as Japan, it’s necessary to go into the current situation and the important factors about the cohabitation of the singles and their parents.
