SILENCER

PURPOSE:To improve freedom of adjustment of silencing frequency in a silencer while securing a sealing property and a falling prevention property of a communicating pipe. CONSTITUTION:By arranging a resonance silencing chamber 4 on an outer part of an intake duct 3, superposing a duct side connection pipe 5 projectively provided from the intake duct 3 and a muffling chamber side connection pipe 6 projectively provided from the resonance silencing chamber 4 so that the former comes to be outside and the latter inside and fastening them from outside by a fastening tool 7, a communicating pipe 8 to communicate the intake duct 3 and the resonance muffling chamber 4 through to each other is formed. On the inside of the communicating pipe 8, a contracted part 12 is provided, and on the contracted part 12, a communicating hole 13 inner diameter D of which smaller than inner diameter of the communicating pipe 8 and hole length L1 of which is shorter than pipe length of the communicating pipe 8 is formed.