A muffler of a muffler made of a titanium alloy wherein advantages of lightness and corrosion-resistance that the titanium alloy originally has are used, and heat-resistance and oxidization-resistance are heightened without damaging costs or workability so that the span of life and flexibility for design are improved. A muffler made of a titanium alloy, wherein the titanium alloy comprises 0.5-2.3% by mass of Al and optionally one or more other alloying elements. The metal texture may comprise more than 90% by volume of the null phase and 20% or less of the null phase. This muffler is superior in heat-resistance, oxidization-resistance, weldability and so on.