To provide a structure for breakwater which has substantially the same slid resistance and fall resistance with a conventional breakwater, and can be constructed in a short period of construction because of problems of a conventional structure for breakwater taking trouble to tow a concrete caisson, and requiring a large amount of a filler for installation construction, a long period of construction, and much cost.

There is provided a structure 10 for breakwater which is made of precast concrete and includes: a foundation part 12 grounded on a top part of a foundation mound provided on a water bottom or ground surface; a main body part 14 which is raised substantially upright from the foundation part and has a water breaking surface; and a buttress 16 which is provided substantially at right angles to the foundation part and wave breaking surface, in which a ground anchor 4 is made capable of being inserted into the water bottom or ground surface from the top part of the main body part 14 or the foundation part.