Various studies have shown that mindfulness promotes well-being. Observing, which is a factor of mindfulness, is surmised as having a core role in promoting well-being. The adaptive effect of observing has been robustly demonstrated in a meditator sample, although that relationship is not always demonstrated in a nonmeditator sample; it is assumed that the factor changed through meditation has an effect on the function of observing. In this study, we relied on the Buddhist psychological model (BPM) and focused on “nonattachment,” which is a flexible, balanced way of relating to one’s experiences without clinging to or suppressing them and is an important concept in the BPM. We discussed nonattachment by using the concepts of “attention” and “moment by moment,” which are concepts shared with psychology. For observing to promote well-being, the results indicate that (1) observation should be flexible with disengaged attention, while being less likely flexible with engaged attention, and should be capable of attentional switching, and (2) observation must be experienced moment by moment.