After fusing the human freezing sperm, the dilution liquid for the human freezing sperm which can suppress the decrease of sperm maneuverability, dilution manner of the human freezing sperm, and the semen for external fertilization of person or the semen for artificial insemination adjustment manner is offered. The dilution liquid for the human freezing sperm contains the calcium ion and the chelating agent which forms the complex, pH is under the 7.4 of 6.75 or more. As for the chelating agent it is desirable to be EGTA, in addition, it is desirable for pH to be the 7.1 or less of 6.9 or more. Dilution manner of the human freezing sperm, fusing the human freezing sperm, makes mix with the dilution liquid for the above-mentioned human freezing sperm. And, the sperm is separated from the dilution liquid for the human freezing sperm after the starting the fusion and within predetermined time.ヒト凍結精子を融解した後の精子運動性の低下を抑制し得るヒト凍結精子用希釈液、ヒト凍結精子の希釈方法、及び、ヒトの体外受精用精液又は人工授精用精液の調整方法を提供する。ヒト凍結精子用希釈液は、カルシウムイオンと錯体を形成するキレート剤を含有し、pHが6.75以上7.4未満である。キレート剤はEGTAであることが好ましく、また、pHが6.9以上7.1以下であることが好ましい。ヒト凍結精子の希釈方法は、ヒト凍結精子を融解して上記ヒト凍結精子用希釈液と混和させる。そして、融解開始後、所定時間以内にヒト凍結精子用希釈液から精子を分離する。
