PURPOSE: To reduce a generating cost through operation of a generating system with high efficiency by providing a primary converting device for wave energy to produce a level difference by means of waves and a water flow air compressing device formed with a water and air suction device and a water and air separating tank.

CONSTITUTION: A primary converting device A for wave energy produces a level difference H1 by means of waves. A water flow air compressing device B is formed with a water and air suction device 5, a down conduit 2, a water and air separating tank 3, and an up conduit 4. An air turbine generating device C is driven by means of compressed air generated by the water air compressing device B. This constitution enables sharp reduction of a generating cost through running of a wave generating system with high efficiency.