A method of manufacturing a clad material which is composed of a core material and two or more skin materials which are superposed on either one or both faces of the core material, the method of manufacturing the clad material comprising: a core material preparation process where an ingot for core material is manufactured by dissolving and casting a metal for core material; a skin material preparation process where an ingot for a first skin material is manufactured by dissolving and casting a metal for skin material different from the metal for core material in their component compositions, and characterized in that the first skin material is manufactured by a slice process in which the ingot for the first skin material is sliced into a predetermined thickness, wherein after the slice process the surface of the sliced first skin material having a predetermined thickness is further subjected to a surface smoothing treatment; and further characterized by the following steps: a rolled plate for skin material preparation process where a rolled plate for a second skin material is manufactured by dissolving and casting a metal for skin material different from the metal for core material in their component compositions, and by further hot-rolling the second skin material; a superposition process where a superposed material is manufactured by superposing the ingot for the first skin material and the rolled plate for the second skin material as skin materials at a predetermined position on either one or both faces of the ingot for core material; and a clad hot-rolling process where a clad material is manufactured by hot-rolling the superposed material. a core material preparation process where an ingot for core material is manufactured by dissolving and casting a metal for core material; a skin material preparation process where an ingot for a first skin material is manufactured by dissolving and casting a metal for skin material different from the metal for core material in their component compositions, and characterized in that the first skin material is manufactured by a slice process in which the ingot for the first skin material is sliced into a predetermined thickness, wherein after the slice process the surface of the sliced first skin material having a predetermined thickness is further subjected to a surface smoothing treatment; and further characterized by the following steps: a rolled plate for skin material preparation process where a rolled plate for a second skin material is manufactured by dissolving and casting a metal for skin material different from the metal for core material in their component compositions, and by further hot-rolling the second skin material; a superposition process where a superposed material is manufactured by superposing the ingot for the first skin material and the rolled plate for the second skin material as skin materials at a predetermined position on either one or both faces of the ingot for core material; and a clad hot-rolling process where a clad material is manufactured by hot-rolling the superposed material. a rolled plate for skin material preparation process where a rolled plate for a second skin material is manufactured by dissolving and casting a metal for skin material different from the metal for core material in their component compositions, and by further hot-rolling the second skin material; a superposition process where a superposed material is manufactured by superposing the ingot for the first skin material and the rolled plate for the second skin material as skin materials at a predetermined position on either one or both faces of the ingot for core material; and a clad hot-rolling process where a clad material is manufactured by hot-rolling the superposed material.