Abstract: The present invention provides an adhesive tape containing a substrate and an adhesive layer formed on at least one side of the substrate, wherein the substrate contains an olefin polymer and a flame retardant, but substantially no halogen atom, and the adhesive tape has a thermal deformation at 100° C. of not more than 65%. The present invention also provides a substrate containing an olefin polymer and a flame retardant, but substantially no halogen atom, wherein the olefin polymer contains the following Component A and Component B: Component A: a thermoplastic resin having a carbonyl oxygen atom in the molecular skeleton Component B: a polymer alloy containing an ethylene component and a propylene component. The adhesive tape and the substrate for the adhesive tape of the present invention are free of generation of dioxin and toxic gas upon incineration, and show superior resistance to thermal deformation, flame resistance and superior stretchability in combination.