To provide a method and apparatus for producing a foamed plastic sheet having a large number of sealed air cells in which the row of low caps exists in the width direction at each desired distance.

With the use of a device having a closing means 4 in which a large number of cavities 11 are provided in the surface of a metallic cylinder, and the bottoms of the cavities 11 are connected by a vacuum suction route 12 running in the axial direction of the cylinder and which rotatably supports a vacuum forming roll 1 with the vacuum suction route 12 opened to a vacuum suction hole 13 at the end of the cylinder, is connected to a vacuum source 5 when the vacuum suction hole 13 comes to a specified rotational position, and partially or entirely prevents the connection of the vacuum suction hole being at the specified position with the vacuum source 5, the molding of the above cap film is implemented. By selecting and changing the position of the closing means 4, a position where the row of the low caps exists is selected in the foamed plastic sheet.

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