As part our investigation into the Galactic rotation curve, we carried out Very Long Baseline Interferometry (VLBI) observations towards the star-forming region IRAS 01123+6430 using VLBI Exploration of Radio Astrometry (VERA) to measure its annual parallax and proper motion. The annual parallax was measured to be 0.151 ± 0.042 mas, which corresponds to a distance of D = 6.61+–215544 kpc, and the obtained proper motion components were (μαcosδ, μδ) = (–1.44 ± 0.15, –0.27 ± 0.16) mas yr–1 in equatorial coordinates. Assuming Galactic constants of (R00) = (8.05 ± 0.45 kpc, 238 ± 14 km s–1), the Galactocentric distance and rotation velocity were measured to be (R, ) = (13.04 ± 2.24 kpc, 239 ± 22 km s–1), which are consistent with a flat Galactic rotation curve. The newly estimated distance provides a more accurate bolometric luminosity of the central young stellar object, LBol = (3.11 ± 2.86) × 103 L, which corresponds to a spectral type of B1–B2. Analysis of 12CO (J = 1–0) survey data obtained with the Five College Radio Astronomical Observatory (FCRAO) 14 m telescope shows that the molecular cloud associated with IRAS 01123+6430 consists of arc-like and linear components, which matches well a structure predicted by numerical simulation of the cloud–cloud collision phenomenon. The coexistence of arc-like and linear components implies that the relative velocity of the two initial clouds was as slow as 3–5 km s–1, which meets the expected criteria of massive star formation where the core mass is effectively increased in the presence of low relative velocity (∼3–5 km s–1), as suggested by Takahira, Tasker, and Habe (2014, ApJ, 792, 63).