A sound-absorbing air duct for a vehicle containing a polyester fiber having a low melting point, the duct comprising: a lower non-woven fabric and an upper non-woven fabric sandwiching wires therebetween; and a film made of a polyester resin having a low melting point and disposed on the upper non-woven fabric, characterized in that each of the lower and upper non-woven fabrics (130, 150) includes a mixture between a first polyester fiber containing a polyester resin having a melting point higher than 250°C and a second polyester fiber containing a polyester resin having a low melting point and having a softening point of 100°C to 150°C, wherein the second polyester fiber includes a polyester resin having a low melting point composed of: an acid component including terephthalic acid or an ester-forming derivative thereof; and a diol component including 2-methyl-1,3-propanediol, 2-methyl-1,3-pentanediol, and ethylene glycol, wherein the 2-methyl-1,3-propanediol is contained at a content of 20 to 50 mol% based on a total content of the diol components of the polyester resin having the low melting point in order to achieve the low melting point properties and improve the adhesion, and wherein the 2-methyl-1,3-pentanediol in the polyester resin having the low melting point constituting the second polyester fiber is contained at a content of 0.01 to 5 mol% based on a total content of the diol components. a lower non-woven fabric and an upper non-woven fabric sandwiching wires therebetween; and a film made of a polyester resin having a low melting point and disposed on the upper non-woven fabric, characterized in that each of the lower and upper non-woven fabrics (130, 150) includes a mixture between a first polyester fiber containing a polyester resin having a melting point higher than 250°C and a second polyester fiber containing a polyester resin having a low melting point and having a softening point of 100°C to 150°C, wherein the second polyester fiber includes a polyester resin having a low melting point composed of: an acid component including terephthalic acid or an ester-forming derivative thereof; and a diol component including 2-methyl-1,3-propanediol, 2-methyl-1,3-pentanediol, and ethylene glycol, wherein the 2-methyl-1,3-propanediol is contained at a content of 20 to 50 mol% based on a total content of the diol components of the polyester resin having the low melting point in order to achieve the low melting point properties and improve the adhesion, and wherein the 2-methyl-1,3-pentanediol in the polyester resin having the low melting point constituting the second polyester fiber is contained at a content of 0.01 to 5 mol% based on a total content of the diol components. an acid component including terephthalic acid or an ester-forming derivative thereof; and a diol component including 2-methyl-1,3-propanediol, 2-methyl-1,3-pentanediol, and ethylene glycol, wherein the 2-methyl-1,3-propanediol is contained at a content of 20 to 50 mol% based on a total content of the diol components of the polyester resin having the low melting point in order to achieve the low melting point properties and improve the adhesion, and wherein the 2-methyl-1,3-pentanediol in the polyester resin having the low melting point constituting the second polyester fiber is contained at a content of 0.01 to 5 mol% based on a total content of the diol components.