A method for manufacturing a droplet-discharging head substrate, the substrate including: a first plate having a plurality of nozzle holes)211) to discharge droplets; and a second plate bonded to a surface of the first plate opposite to a droplet-discharging surface from which the droplets are discharged, the second plate having a plurality of through-holes communicating with the respective nozzle holes to form a plurality of flow paths, the method comprising: a first step to perform a surface activation process on surfaces of the first and second plates (21, 22) to be joined with an atom beam, an ion beam, or a plasma as an energy wave; a second step to align and stack the first and second plates (21, 22) in such a manner that the nozzle holes formed in the first plate communicate with the respective through-holes formed in the second plate; and a third step to bond the surfaces of the stacked first and second plates to each other by atomic bonding without covalent bonding caused by ion movement, wherein the third step bonds the surfaces to be joined by bringing a load member into contact with the droplet-discharging surface of the first plate at a position away from the nozzle holes and applying a pressure to the droplet-discharging surface under an atmospheric pressure, and by bringing the surfaces to be joined close to each other with an electrostatic attractive force generated between the surfaces to be joined. a first plate having a plurality of nozzle holes)211) to discharge droplets; and a second plate bonded to a surface of the first plate opposite to a droplet-discharging surface from which the droplets are discharged, the second plate having a plurality of through-holes communicating with the respective nozzle holes to form a plurality of flow paths, the method comprising: a first step to perform a surface activation process on surfaces of the first and second plates (21, 22) to be joined with an atom beam, an ion beam, or a plasma as an energy wave; a second step to align and stack the first and second plates (21, 22) in such a manner that the nozzle holes formed in the first plate communicate with the respective through-holes formed in the second plate; and a third step to bond the surfaces of the stacked first and second plates to each other by atomic bonding without covalent bonding caused by ion movement, wherein a first step to perform a surface activation process on surfaces of the first and second plates (21, 22) to be joined with an atom beam, an ion beam, or a plasma as an energy wave; a second step to align and stack the first and second plates (21, 22) in such a manner that the nozzle holes formed in the first plate communicate with the respective through-holes formed in the second plate; and a third step to bond the surfaces of the stacked first and second plates to each other by atomic bonding without covalent bonding caused by ion movement, wherein the third step bonds the surfaces to be joined by bringing a load member into contact with the droplet-discharging surface of the first plate at a position away from the nozzle holes and applying a pressure to the droplet-discharging surface under an atmospheric pressure, and by bringing the surfaces to be joined close to each other with an electrostatic attractive force generated between the surfaces to be joined.