ABSTRACTThis study examined the cognitive characteristics of navigational map use by mountaineers. Questionnaires regarding navigation skill and behavior were completed by 362 mountaineers and contour tasks by 155 mountaineers, who participated in a practical course on mountaineering skills. A confirmatory factor analysis of the questionnaire confirmed three cognitive components of map use: Carrying and reference to map and compass; Symbol understanding and Solution of navigational tasks. The score of each cognitive component and the contour tasks differently improved with map-use experience. Gender difference was obtained only in the Line-of-sight task. Another confirmatory factor analysis of questionnaire and contour tasks showed good fit. Contour interpretation skills strongly explained the Navigational map use, which was the second factor from the above three components. The results suggest: (a) contour interpretation is a multifaceted cognitive task consisting of two-dimensional pattern recognition and three-dimensional transformation, (b) map-use skills consist of problem-solving of navigation in addition to basic understanding of map symbols and (c) even the mountaineers with long experience do not necessarily acquire full skills of contour interpretation but solve navigational problems with available cognitive skills, which were acquired in the constraint of the environment.