Few studies have investigated the imagery experiences that occur during scale responses on the mental imagery vividness scale. The current study examined and categorizes such imagery experiences. A total of 68 adults were presented with visual items of the Japanese version of the Plymouth Sensory Imagery Questionnaire (Psi-Q) online. They were then asked to write freely about the imagery experiences. The results of the KJ method revealed three major categories of such experiences: cases in which i) only visual imagery, ii) unspecified sensory modality imagery, and iii) an emotional experience occurred. Next, the visual imagery was classified along six axes (movement, source, realism, presence, perspective, and range of imagined objects). According to these results, various imagery experiences occurred during the scale responses. Future studies should examine the influence of such experiences on vividness measures.