To obtain a flame-retarding adhesive tape free from generation of hydrogen halide in combustion, exhibiting sufficient adhesive force without using an adhesive and having improved flame-retardancy by including a metal hydroxide and a lubricant, etc., in a mixture of an ethylene-acrylic acid ester copolymer and an amorphous propylene-ethylene copolymer.

(A) A mixture of (i) an ethylene-acrylic acid ester copolymer and (ii) an amorphous propylene-ethylene copolymer is incorporated with (B) a metal hydroxide such as magnesium hydroxide, aluminum hydroxide or calcium hydroxide, (C) a lubricant such as stearic acid or silicone and, as necessary, (D) an antioxidant such as hindered phenol antioxidant, (E) a flame- retarding assistant, (F) a crosslinking agent and (G) a crosslinking assistant. The mixing ratio of the component (i) to the component (ii) in the mixture A is preferably 6:4 to 2:8. Similar effect can be attained by replacing the component (i) with a low-crystalline polypropylene.