An array device for biomolecule quantification comprising: a base having a plurality of wells; a cover having a gap between the base and the cover and laid over the base to cover openings of the plurality of wells; an injection port communicating with the gap between the base and the cover; a discharge port formed at a position apart from the injection port and communicating with the gap between the base and the cover, said array device being configured so that an aqueous solution may be filled in between the base and the cover; said injection port being configured to: introduce a liquid containing biomolecules into the gap between the base and the cover to transfer the biomolecules by diffusion to the aqueous solution filled in the plurality of wells; said discharge port being configured to discharge, by introducing said liquid, surplus aqueous solution, the surplus aqueous solution being outside the plurality of wells, said array device for biomolecule quantification further comprising a waste liquid vessel formed in the cover and communicating with the discharge port and collecting liquid that flows in from the gap between the base and the cover via the discharge port, wherein a bottom surface of the waste liquid vessel is at a higher level of the gap between the base and the cover in a thickness direction of the base, an injection port opening end of the injection port is at a lower level than the level of a waste liquid vessel side opening end of the discharge port in the thickness direction of the base, and the waste liquid vessel side opening end is at a higher level than the level of the bottom surface of the waste liquid vessel in a thickness direction of the base. a base having a plurality of wells; a cover having a gap between the base and the cover and laid over the base to cover openings of the plurality of wells; an injection port communicating with the gap between the base and the cover; a discharge port formed at a position apart from the injection port and communicating with the gap between the base and the cover, said array device being configured so that an aqueous solution may be filled in between the base and the cover; said injection port being configured to: introduce a liquid containing biomolecules into the gap between the base and the cover to transfer the biomolecules by diffusion to the aqueous solution filled in the plurality of wells; said discharge port being configured to discharge, by introducing said liquid, surplus aqueous solution, the surplus aqueous solution being outside the plurality of wells, said array device for biomolecule quantification further comprising a waste liquid vessel formed in the cover and communicating with the discharge port and collecting liquid that flows in from the gap between the base and the cover via the discharge port, wherein a bottom surface of the waste liquid vessel is at a higher level of the gap between the base and the cover in a thickness direction of the base, an injection port opening end of the injection port is at a lower level than the level of a waste liquid vessel side opening end of the discharge port in the thickness direction of the base, and the waste liquid vessel side opening end is at a higher level than the level of the bottom surface of the waste liquid vessel in a thickness direction of the base. introduce a liquid containing biomolecules into the gap between the base and the cover to transfer the biomolecules by diffusion to the aqueous solution filled in the plurality of wells; said discharge port being configured to discharge, by introducing said liquid, surplus aqueous solution, the surplus aqueous solution being outside the plurality of wells, said array device for biomolecule quantification further comprising a waste liquid vessel formed in the cover and communicating with the discharge port and collecting liquid that flows in from the gap between the base and the cover via the discharge port, wherein a bottom surface of the waste liquid vessel is at a higher level of the gap between the base and the cover in a thickness direction of the base, an injection port opening end of the injection port is at a lower level than the level of a waste liquid vessel side opening end of the discharge port in the thickness direction of the base, and the waste liquid vessel side opening end is at a higher level than the level of the bottom surface of the waste liquid vessel in a thickness direction of the base.