Human errors are not unusual characters to be inherent in the specific individuals or environments, and they are certain results influenced by each occasion and situation. Strictly, the characteristics of human reliability, accuracy, vitality, and so on, always changes, so our any acts might to become errors depending on the circumstances. To attempt the accident prevention measures caused by human errors, it is necessary to grasp the process of the accident-occurrence in detail. Especially, what relation the human factors had had among the various accidents causes, and how the psychological condition of victim had been, should be considered carefully. In this research, four labour accident-cases are extracted from 191 accident-cases which occurred in 2000 in Japanese construction work. And the relations among the psychological factors of victims, the processes of the accident-occurrence, and error factors are discussed, including the supposition of the researcher.