A solder layer and an electronic device bonding substrate having high bonding strength of a device and low bonding failure even by a simplified bonding method of a device to a substrate and a method for manufacturing the same are provided.A device bonding substrate 1 including a substrate 2 and a lead free solder layer 5 formed on said substrate has a solder layer 5 consisting of a plurality of layers having mutually different phases, and oxygen concentration on the upper surface of the solder layer is lower than 30 atomic % of the concentration of the metal component which is the most oxidizable among the metal components making up the upper layer of the solder layer 5. Carbon concentration on the upper surface of the solder layer 5 may be lower than 10 atomic % of the concentration of the metal component which is the most oxidizable among the metal components making up the upper layer of the solder layer.