Abstract: To provide a new technique for efficiently recovering microplastics from water to be treated, in which problems of conventional techniques such as large energy consumption are solved. A method for recovering microplastics from water to be treated containing the microplastics, the method comprising a step of allowing algae having microplastic adsorption and recovery ability to be present in the water to be treated, in which the algae are algae that secrete a sticky substance, and an amount of a sticky substance secreted by the algae is such that a volume of a sticky substance secreted to an outside of cells is 0.25 times or more and 100 times or less compared to a cell volume.