Multilayer sheet and production method thereof

A method of producing a multilayer sheet, the method comprising:

• preparing a substrate layer (A) that comprises a polyphenylene ether, an adhesive layer (B) that comprises an acid-modified polyolefin, and a tie layer (C) that comprises a polyolefin/polyphenylene ether-based alloy;
• bringing the substrate layer (A) and the tie layer (C) into contact with each other in a molten state of 160° C. or higher of at least one of the substrate layer (A) or the tie layer (C);
• and
• at the same time as or a different time from bringing the substrate layer (A) and the tie layer (C) into contact with each other, bringing the tie layer (C) and the adhesive layer (B) into contact with each other in a molten state of 160° C. or higher of at least one of the tie layer (C) or the adhesive layer (B).