As AI has become ubiquitous in society, there has been an increasing number of discussions examining the pros and cons of using AI in court proceedings. Against this background, this study examined (1) the extent to which citizens support the use of AI in trials, and (2) what factors determine their support. A questionnaire survey was administered to 783 respondents. Results indicated: (1) Many respondents were not positive about the use of AI in trials; (2) Support for the use of AI in trials was negatively associated with the image that AI is capable of only mechanical processing and cannot give "warm" judgments like human judges ("inhuman image") and the image that using AI makes the trial process opaque ("opaque image"). On the other hand, the use of AI was positively associated with the image that the trial process would be fairer and less biased than that of human judges ("fair image").