A device for sampling blood and measuring erythrocyte sedimentation rate. The device comprises a tube with one end closed, a blood sampling portion on an opened end of the tube and an erythrocyte sedimentation rate measuring portion extending from the blood sampling portion. A stopper is located on the open end of said tube, and may be pierced with a blood drawing needle. Finally a partition member is located within said tube and extends substantially over the entire length of said tube. Blood is directly sampled into the device and the device mixes the sampled blood with a solution of an anticoagulant with a high efficiency in the device. Accordingly, measurement of erythrocyte sedimentation rate can be performed quickly and easily.