Provided is a galectin-9 variant that retains substantially the same physiological activity as wild-type galectin-9 and is excellent in protease stability, solubility, and yield. The galectin-9 variant of the present invention has the following NCRD and the following CCRD comprising an N-terminal region and a C-terminal region, and the C-terminal of the NCRD and the N-terminus of the CCRD are bound directly or indirectly. It is a protein. The NCRD is a peptide consisting of the amino acid sequence represented by (N1) SEQ ID NO: 1. The N-terminal region of CCRD is a peptide consisting of an amino acid sequence in which 1 to 17 amino acids are deleted in the amino acid sequence represented by (C-N1) SEQ ID NO: 3, and the C-terminal region is (C- C1) A peptide consisting of the amino acid sequence represented by SEQ ID NO: 5.野生型ガレクチン９と実質的に同質の生理活性を保持し、且つ、プロテアーゼ安定性、溶解性および収率に優れるガレクチン９改変体を提供する。 本発明のガレクチン９改変体は、Ｎ末端領域およびＣ末端領域からなる下記ＮＣＲＤと下記ＣＣＲＤとを有し、前記ＮＣＲＤのＣ末端と前記ＣＣＲＤのＮ末端とが、直接的または間接的に結合したタンパク質である。前記ＮＣＲＤは、（Ｎ１）配列番号１で表わされるアミノ酸配列からなるペプチド。前記ＣＣＲＤのＮ末端領域は、（Ｃ－Ｎ１）配列番号３で表わされるアミノ酸配列において、１～１７個のアミノ酸が欠失したアミノ酸配列からなるペプチドであり、前記Ｃ末端領域は、（Ｃ－Ｃ１）配列番号５で表わされるアミノ酸配列からなるペプチド。
