本稿では「ビニ傘」の「ビニ」、「コスパ」の「コス」「パ」などのような、単独用法もなく、意味的にも形態的にも不完全な省略形外来語形態素を分析の対象として取り上げ、その語構成的な考察を行う。まず、省略形外来語形態素自身を、省略前の元語基との関わりや形態、結合相手などの語構成的な側面から分析したところ、省略形外来語形態素は、大多数（9割以上）は、その元語基の外来語が日本語に存在し、そして半分以上がいわゆる「唯一形態素」であり、全体的には生産性が低いことが確認できた。次に、意味も語形も不完全な省略形外来語形態素が日本語の形態素として機能し得る理由も解明できた。それから、「ロケ」や「レジ」といった外来語省略語基、また特殊な短縮形拘束語基「-コン」との比較を通して、省略形外来語形態素は形態的．意味的には外来語省略語基とは異なる性格を有するが、「-コン」とは近似し、省略前の元語基へ依存する短縮形拘束語基だと位置づけた。最後に、省略形外来語形態素どうしでの複合略語が英語の混成語（blend）と似ているという日本語の語彙としての造語性質も述べた。｜The analysis subjects in this thesis are the Japanese loanword morpheme abbreviations with incomplete meaning and form, which also cannot be used separately, such as ＂BINI＂ from the word ＂BINAGASA＂ and ＂KOSU＂ and ＂PA＂ from the word ＂KOSUPA＂, in order to conduct the word formation study First we focus on the Japanese loanword morpheme abbreviation itself to analyze from word formation aspect, such as the relation, form, and the combined words between the original word and its abbreviation Then we found out that there are more than half the Japanese loanword morpheme abbreviations are ＂sole morphemes＂ with low productivity as a whole. Second, we clarify the reason why the Japanese loanword morpheme abbreviations become Japanese morpheme. In addition, by analyzing and comparing with loanword abbreviated base morpheme such as ＂ROKE＂ and ＂REJI＂, and the special bound abbreviated base such as ＂-KON＂, we can understand that the Japanese loanword morpheme abbreviations' form and meaning are different from loanword abbreviated base, but similar to ＂-KON＂. So, we locate the Japanese loanword morpheme abbreviations as a bound abbreviated base which rely on the original base And last, we elaborate the similarity in Japanese word formation character between the compound abbreviations connected by two Japanese loanword morpheme abbreviations and the English hybrid word(blend)