We have developed a millimeter and submillimeter Michelson-type bolometric interferometer based on a Martin–Puplett-type Fourier-transform spectrometer named multi-Fourier-transform interferometer (MuFT). We have succeeded in proving that the MuFT is capable of performing broadband imaging observations as theoretically proposed by our previous paper (OHM) [Appl. Opt. 45, 2576 (2006)]. We succeeded in acquiring the mutual coherence signal for an extended source in broadband. By analyzing the obtained mutual coherence signal following the formula proposed in OHM, 2D source images for each wavenumber from 5{\mathrm{cm}}^{-1}\left(150\mathrm{GHz}\right) to 35{\mathrm{cm}}^{-1}\left(1.05\mathrm{THz}\right) with a wavenumber interval of 0.4{\mathrm{cm}}^{-1}\left(12\mathrm{GHz}\right) were successfully extracted. The large dynamic range advantage of the MuFT proposed in OHM was confirmed experimentally.