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We report the trigonometric parallax of IRAS 07427-2400 with VERA to be 0.185$\pm$ 0.027 mas, corresponding to a distance of 5.41$^{+0.92}_{-0.69}$ kpc. Theresult is consistent with the previous result of 5.32$^{+0.49}_{-0.42}$ kpcobtained by Choi et al. (2014) within error. To remove the effect of internalmaser motions (e.g., random motions), we observed six maser features associatedwith IRAS 07427-2400 and determined systematic proper motions of the source byaveraging proper motions of the six maser features. The obtained proper motionsare ($\mu_{\alpha}$cos$\delta$, $\mu_{\delta}$) = ($-$1.79 $\pm$ 0.32, 2.60$\pm$ 0.17) mas yr$^{-1}$ in equatorial coordinates, while Choi et al. (2014)showed ($\mu_{\alpha}$cos$\delta$, $\mu_{\delta}$) = ($-$2.43 $\pm$ 0.02, 2.49$\pm$ 0.09) mas yr$^{-1}$ with one maser feature. Our astrometry results placethe source in the Perseus arm, the nearest main arm in the Milky Way. Using ourresult with previous astrometry results obtained from observations of thePerseus arm, we conducted direct (quantitative) comparisons between 27astrometry results and an analytic gas dynamics model based on the density-wavetheory and obtained two results. First is the pitch angle of the Perseus armdetermined by VLBI astrometry, 11.1 $\pm$ 1.4 deg, differing from what isdetermined by the spiral potential model (probably traced by stars), $\sim$ 20deg. The second is an offset between a dense gas region and the bottom of thespiral potential model. The dense gas region traced by VLBI astrometry islocated downstream of the spiral potential model, which was previouslyconfirmed in the nearby grand-design spiral galaxy M51 in Egusa et al. (2011).

Outer Rotation Curve of the Galaxy with VERA III: Astrometry of IRAS 07427-2400 and Test of the Density-Wave Theory