This paper considers the effect of whether burden of proof is assigned to plaintiffs or defendants in tort claims on the defendant’s care-taking incentive under the possibility of judicial error. We argue that it is socially better to place burden of proof on the plaintiff if the proof costs of both parties are low and the evidence is very accurate, thus reducing the wasteful incentive for defendants to commit over-precaution. If the burden of proof is placed on the defendant, it exacerbates the defendant’s over-precaution due to an accident avoidance effect whereby the defendant is incentivized to take more care to avoid an accident, thereby saving evidence costs. We also discuss the sine qua non rule in the case ofnoisy evidence and reconfirm the accident-avoidance effect. This is compared to the result of Gómez (2002).