PURPOSE: To install an artificial beach in any sea area in a simple manner and carry out the restoration of the original state of an installed sea area in a simple manner.

CONSTITUTION: In a sea area 2, a floating beach 3 which is constituted of a pontoon body 4 which is floatatable and shiftable as a semisubmerged body and a beach 11 such as sand beach 12 and a sea shore which is constructed on the deck of the pontoon body 4 is moored in the front surface sea area 2 along a protected shore. Accordingly, since the floating beach 3 is shiftable, the restoration of the original state of the installed sea area 2 can be carried out in a simple manner, and the biological system in the contiguous sea area is prevented from bein given with influences.