An apparatus and method for measuring an erythrocyte sedimentation rate based on a change in conductivity of blood over time. The apparatus for measuring an erythrocyte sedimentation rate may include: a chamber for holding blood; a pair of electrodes being partially or completely brought into contact with the blood; and a conductivity meter measuring the conductivity through the pair of electrodes. The apparatus and method according to the present invention are less time-consuming than the Westergren method and can acquire a variety of information (for example, hematocrit, dynamics of the sedimentation rate and aggregation of erythrocytes, a relationship between the sedimentation rate and aggregation of erythrocytes, and the like).