A wave power utilization device comprising: a wave receiving box having a wave receiving box inlet that receives push and pull of waves of seawater, and having a space filled with the seawater that flows in from the wave receiving box inlet; a hollow compression pipe connected to communicate with an inside of the wave receiving box, the hollow compression pipe having an upper opening and a lower opening which is set to have a wider flow path cross-sectional area than a flow path cross-sectional area of the upper opening, the hollow compression pipe including a tapered section, a wave drawing section, and an air compressing section, the tapered section connecting the lower opening and the upper opening to each other in a tapered shape, the wave drawing section drawing the waves drawn into the wave receiving box through the tapered section, the air compressing section compressing air by the drawn waves; a gas-liquid introduction on-off valve which is connected to an upper part of the wave drawing section, and performs an opening operation to allow the air or the seawater to flow in and out; an air discharge pipe connected to an upper part of the air compressing section and having a check valve that allows a flow of the air only in a downstream direction from the air compressing section; a compressed air storage tank connected to a downstream side of a flow path of the air discharge pipe, and filled with the air compressed by the air compressing section; an air introduction unit which introduces the air into the air compressing section; an air introduction pipe which connects the air introduction unit and the air compressing section to each other; and an air introduction on-off valve provided in a middle of the air introduction pipe and capable of introducing the air from the air introduction unit into the air compressing section during an opening operation. a wave receiving box having a wave receiving box inlet that receives push and pull of waves of seawater, and having a space filled with the seawater that flows in from the wave receiving box inlet; a hollow compression pipe connected to communicate with an inside of the wave receiving box, the hollow compression pipe having an upper opening and a lower opening which is set to have a wider flow path cross-sectional area than a flow path cross-sectional area of the upper opening, the hollow compression pipe including a tapered section, a wave drawing section, and an air compressing section, the tapered section connecting the lower opening and the upper opening to each other in a tapered shape, the wave drawing section drawing the waves drawn into the wave receiving box through the tapered section, the air compressing section compressing air by the drawn waves; a gas-liquid introduction on-off valve which is connected to an upper part of the wave drawing section, and performs an opening operation to allow the air or the seawater to flow in and out; an air discharge pipe connected to an upper part of the air compressing section and having a check valve that allows a flow of the air only in a downstream direction from the air compressing section; a compressed air storage tank connected to a downstream side of a flow path of the air discharge pipe, and filled with the air compressed by the air compressing section; an air introduction unit which introduces the air into the air compressing section; an air introduction pipe which connects the air introduction unit and the air compressing section to each other; and an air introduction on-off valve provided in a middle of the air introduction pipe and capable of introducing the air from the air introduction unit into the air compressing section during an opening operation.