A cultured algae water concentration system comprising: an algae water supply unit that receives algae water containing cultured algae from a culture pond, stores the algae water therein, and has an algae water supply container that stores the algae water therein, a supply container inlet port through which the algae water supply container takes in the algae water, and a supply container outlet port through which the algae water is taken out from the algae water supply container; and an algae water concentration unit that concentrates the algae water which has been supplied from the algae water supply unit, and that has a concentration container for receiving and concentrating the algae water, a filter that divides the concentration container into upper and lower spaces and does not pass algae having a predetermined size or larger therethrough, a vibration device that vibrates the filter in an out-of-plane direction, a concentration container algae water inlet port that is in communication with the supply container outlet port, takes in the algae water to the concentration container, and is arranged below the filter of the concentration container, a concentrated algae water outlet port that is arranged below the filter of the concentration container and takes out algae water therethrough that has been concentrated in the concentration container, and a filtered water discharge port that is arranged above the filter of the concentration container and discharges filtered water having passed through the filter, wherein the filter is made of an electroformed sheet filter made from metal or a metal mesh. an algae water supply unit that receives algae water containing cultured algae from a culture pond, stores the algae water therein, and has an algae water supply container that stores the algae water therein, a supply container inlet port through which the algae water supply container takes in the algae water, and a supply container outlet port through which the algae water is taken out from the algae water supply container; and an algae water concentration unit that concentrates the algae water which has been supplied from the algae water supply unit, and that has a concentration container for receiving and concentrating the algae water, a filter that divides the concentration container into upper and lower spaces and does not pass algae having a predetermined size or larger therethrough, a vibration device that vibrates the filter in an out-of-plane direction, a concentration container algae water inlet port that is in communication with the supply container outlet port, takes in the algae water to the concentration container, and is arranged below the filter of the concentration container, a concentrated algae water outlet port that is arranged below the filter of the concentration container and takes out algae water therethrough that has been concentrated in the concentration container, and a filtered water discharge port that is arranged above the filter of the concentration container and discharges filtered water having passed through the filter, wherein the filter is made of an electroformed sheet filter made from metal or a metal mesh. <EOS>