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tokens: adopt κ 140 μ m = 13.9 cm 2 g −1 ( Draine 2003a ). We also calculate the optical depth of the silicate feature τ sil , following the method defined by Imanishi et al. (2007) where an absorption-free continuum is assumed to be the power-law function determined from the flux densities at 7.1 and 14.2 μ m. As a result, τ sil is estimated to be 2.3 ± 0.2 at 9.8 μ m, the wavelength of the bottom of the absorption feature. We also performed the SED fitting of the heavily obscured AGN, using the Bayesian SED fitting code CIGALE ( Burgarella et al. 2005 ; Noll et al. 2009 ; Boquien et al. 2019 ), which includes energy balance between the dust absorption of the stellar/AGN emission and the dust re-emission in the mid- to far-IR, similarly to the study by Ciesla et al. (2015) . As a result, M star and L IR are estimated to be 8 × 10 9 M ⊙ and 6 × 10 10 L ⊙ , respectively. Comparing the result in Table 3 , we find that M star increases while L IR does not change. The increase in M star , however, does not change our conclusion below. 4. Discussion 4.1. Comparison with other AGNs We detect a deep ( τ sil ∼ 2.3) absorption feature due to silicate grains at around 10 μ m. We compared the optical depth of the silicate feature in LEDA 1712304 with those in other AGNs in a wide range of IR luminosities (10 10 L ⊙ L IR 10 13 L ⊙ ). The spectra of the AGNs to be compared are taken from those of the IR galaxies observed by S p i t z e r /IRS ( Stierwalt et al. 2013 ; Imanishi et al. 2007 ; Imanishi 2009 ; Roussel et al. 2006 ) with the threshold that the equivalent width of the PAH 6.2 μ m feature is smaller than 0.27 μ m ( Stierwalt et al. 2013 ). In addition, we also take AGNs with low IR luminosities ( L IR 10 11 L ⊙ ) from Wu et al. (2010) . Figure 3 shows the relation between the IR luminosity and the optical depth of the silicate feature for LEDA 1712304 and the AGNs. We estimated the optical depths of the AGNs of Stierwalt et al. (2013) , Wu et al. (2010) , and Roussel et al. (2006) by ourselves in the same manner as was performed for LEDA 1712304 with the method defined by Imanishi et al. (2007) , the spectra of which were obtained from the NASA/IPAC IR Science Archive (IRSA). On the other hand, we adopted the values given in each reference paper for the other AGNs. The blue dotted lines in Fig. 3 show the differences between our estimates and those by Stierwalt et al. (2013) , which confirms that the differences between the different methods are not large enough to change a global relation. Figure 3 shows that galaxies with low IR luminosities ( L IR 10 11 L ⊙ ) show significantly shallow silicate absorption features, as already pointed out by Stierwalt et al. (2013) . Imanishi (2009) suggested that the number of heavily obscured AGNs that have deep silicate absorption features ( τ sil > 2) increases with the IR luminosities of the host galaxies. Therefore, LEDA 1712304 may be a rare galaxy from the aspect of having both deep absorption feature τ sil ∼