The present invention aims to provide an albumin-sugar chain complex comprising sugar chains sufficient for exhibiting sugar-chain clustering effects, and being able to stably exist in an organism. The present invention provides: an albumin-sugar chain complex comprising five or more molecules of asparagine binding-type sugar chains per one molecule of albumin； a carrier that comprises the albumin-sugar chain complex and selectively delivers a functional molecule to the target tissues in an organism； and a bioimaging prove that comprises the albumin-sugar chain complex as an active ingredient, and is administered to an animal body.本發明之目的在於提供一種白蛋白-糖鏈複合物，其結合有適得糖鏈群聚效應之充分數量的糖鏈，且可在活體內較穩定地存在。本發明提供一種白蛋白-糖鏈複合物，其特徵在於天門冬醯胺結合型糖鏈是在每1分子白蛋白結合有5分子以上；一種機能性分子用載體，其是用以在活體內將機能性分子選擇性地送達目標組織，且含有前述記載之白蛋白-糖鏈複合物；一種生物顯影探針，其特徵在於是以前述記載之白蛋白-糖鏈複合物為有效成分，且投予至動物活體內。
