An acoustic absorbing device includes a housing having a chamber formed by an outer peripheral wall and a bottom wall, a hood engaged into the housing, an absorbing member engaged into the hood, and a silencer engaged into the absorbing member, the silencer and the absorbing member may be selectively attached to the hood or may be easily replaced with the other ones or new or different ones according to different environment. The silencer may include an outer cap extended into or out of the absorbing member. The housing includes one or more couplers for selectively coupling the housing to the other coupling or supporting members.