To provide a howling canceler capable of suppressing howling by accurately detecting a frequency band, in which howling may occur, without incurring howling in an acoustic space actually.

A loudspeaker 1 changes over switches to form a first loop (speaker SP, microphone M, impulse response measuring section 11) and a second loop (filter 16, FIR filter 12). The loudspeaker 1 sets the FIR filter 12 simulating a transfer function of an acoustic feedback system from the speaker SP to the microphone in the first loop, detects a frequency band in which howling may occur by generating a measuring signal in the second loop, and sets the filter 16 suppressing a gain of the frequency band. The loudspeaker 1 changes over the switches to form a third loop (microphone M, amplifier 14, filter 16, speaker SP) and outputs an audio signal inputted to the microphone M to the speaker SP via the filter 16.