A wiring forming method comprising: forming wiring on multiple substrates of different materials by baking a metal-containing liquid that is a liquid containing metal particles, wherein the forming includes applying the metal-containing liquid straddling multiple different types of substrate materials, and baking the metal-containing liquid applied during the applying with a laser , wherein the laser emission amount per unit of area is changed based on the substrate material for each of the multiple substrates when baking the metal-containing liquid , wherein the applying includes applying the metal-containing liquid straddling a first substrate and a second substrate that has at least one of a higher thermal conductivity than the thermal conductivity of the first substrate , a higher thermal capacity than the thermal capacity of the first substrate , or a larger volume than the volume of the first substrate , characterized in that the baking includes a first baking process of baking the metal-containing liquid applied on the first substrate by applying the laser corresponding to a first set emission amount, which is a laser emission amount per unit of area set according to the first substrate , and a second baking process of, after the first baking processing is complete, baking the metal-containing liquid applied on the second substrate by applying the laser corresponding to an emission amount that is equal to or less than a second set emission amount, which is a laser emission amount per unit of area set according to the second substrate , and greater than the first set emission amount. forming wiring on multiple substrates of different materials by baking a metal-containing liquid that is a liquid containing metal particles, wherein the forming includes applying the metal-containing liquid straddling multiple different types of substrate materials, and baking the metal-containing liquid applied during the applying with a laser , wherein the laser emission amount per unit of area is changed based on the substrate material for each of the multiple substrates when baking the metal-containing liquid , wherein the applying includes applying the metal-containing liquid straddling a first substrate and a second substrate that has at least one of a higher thermal conductivity than the thermal conductivity of the first substrate , a higher thermal capacity than the thermal capacity of the first substrate , or a larger volume than the volume of the first substrate , characterized in that the baking includes a first baking process of baking the metal-containing liquid applied on the first substrate by applying the laser corresponding to a first set emission amount, which is a laser emission amount per unit of area set according to the first substrate , and a second baking process of, after the first baking processing is complete, baking the metal-containing liquid applied on the second substrate by applying the laser corresponding to an emission amount that is equal to or less than a second set emission amount, which is a laser emission amount per unit of area set according to the second substrate , and greater than the first set emission amount. <EOS>