Abstract
Beach changes around Misawa fishery harbor facing the Pacific Ocean in Aomori Prefecture were studied by field observation. The breakwaters of this harbor blocked longshore sand transport, and north coast was severely eroded to be artificial coastline protected by many coastal structures, whereas south coast was accreted. Sand supply from further south coast of Misawa fishery harbor is decreasing rapidly. This means that adoption of sand bypassing method, in which sand will be carried from the south side of the harbor to the north coast is impossible, because this newly causes beach erosion on the coasts further south of this harbor. It is needed that harbor breakwater should be regarded as a large-scale headland to stabilize the coastline and returning of sand from the harbor to the further south coast should be considered
