An electronic device characterized by including a substrate, a bonding layer provided on the substrate, the bonding layer containing copper in an amount of greater than 0 mass % but 60 mass % or less, the copper having its crystal grain size of 50 nm or less, an electronic component provided on the bonding layer, and a coating film covering a side of the bonding layer, the coating film containing at least one compound selected from copper (I) oxide (Cu2O) and copper (II) oxide (CuO).