A method of enclosing a microscopic body in at least some of a plurality of cavities, that are formed in a bottom surface of a well that is formed in a substrate, and that are separated from each other, the method comprising: a first step of arranging an insertion member in the space of the well above a cavity-formed surface of the substrate, determining relative positions of the insertion member and the substrate by a support section provided on the insertion member such that a bottom surface of the insertion member and the cavity-formed surface of the substrate face each other, thereby providing a solution introduction space between the bottom surface of the insertion member and the cavity-formed surface of the substrate, and providing a solution discharge space that is in communication with the solution introduction space, the solution discharge space being located above the bottom surface of the insertion member, and between the substrate and the insertion member, within the substrate, and/or within the insertion member; a second step of introducing a first liquid into the solution introduction space, wherein the first liquid includes the microscopic body and a first solvent; and a third step of introducing a second liquid into the solution introduction space, wherein the second liquid includes a second solvent immiscible with the first solvent, discharging, into the solution discharge space, the first liquid introduced into the solution introduction space as a portion of the first liquid introduced into the solution introduction space and the cavities, and thereby forming, within each cavity, a droplet of the first liquid coated with the second liquid and containing the microscopic body. a first step of arranging an insertion member in the space of the well above a cavity-formed surface of the substrate, determining relative positions of the insertion member and the substrate by a support section provided on the insertion member such that a bottom surface of the insertion member and the cavity-formed surface of the substrate face each other, thereby providing a solution introduction space between the bottom surface of the insertion member and the cavity-formed surface of the substrate, and providing a solution discharge space that is in communication with the solution introduction space, the solution discharge space being located above the bottom surface of the insertion member, and between the substrate and the insertion member, within the substrate, and/or within the insertion member; a second step of introducing a first liquid into the solution introduction space, wherein the first liquid includes the microscopic body and a first solvent; and a third step of introducing a second liquid into the solution introduction space, wherein the second liquid includes a second solvent immiscible with the first solvent, discharging, into the solution discharge space, the first liquid introduced into the solution introduction space as a portion of the first liquid introduced into the solution introduction space and the cavities, and thereby forming, within each cavity, a droplet of the first liquid coated with the second liquid and containing the microscopic body.