Summary Chemotaxis of leptospiras was studied using a U‐tube made of a commercially available straw‐shaped polypropylene tube with an uneven flexible part. The U‐tube was made by folding the polypropylene tube double and binding the vertical parts by a piece of tape, thus making the uneven flexible part the bottom. Semi‐solid Korthof's medium was poured into the U‐tube. Preliminary experiments showed that the medium containing 0.5 % agar and measuring 2 cm in length was appropriate. Leptospiras inoculated on the top of the medium of one side of the U‐tube moved toward the top of the medium of the other side. The leptospiral move toward the uninoculated top was significantly faster when 6 μg of hemoglobin were added to the uninoculated top. Chemotaxis of leptospiras to hemoglobin was thus shown, which is the first evidence of chemotaxis of leptospiras.