In medical malpractice litigation, the cooperation of medical experts is important. However, the appointment of experts has become problematic in Japan, apparently because many medical experts refuse to act in this capacity. However, this supposition has not until now been supported by quantitative evidence, since the fact that so few judgments in Japan are published made it impossible to investigate the situation. Therefore, we aim to show the state of the use of experts in medical malpractice litigation using objective data. Over the last ten years, the rate of the use of experts has averaged only 22.5%, varying according to region. Experts were used in 24.5% of cases involving an attorney on the patient's side, and in only 3.4% of cases where no attorney was used. The success rate of patients was higher when experts were adopted (39.1%) than when they were not (29.9%). The length of litigation involving experts was 4.0 years, and 2.7 years when no expert was involved. This research suggested the necessity of establishing a formal cooperation system as soon as possible in Japan with no regional maldistribution.