Edge impurity transport has been studied in the stochastic magnetic field layer called the ergodic layer of the Large Helical Device. Chord-integrated full vertical profiles of C IV (312.4 Å: 1s23p–1s22s) near edge X-points are observed at horizontally elongated plasma cross sections. Measured C IV profiles are almost flat at low density (⩽2 × 1013 cm−3), while two peaks called the 'X-point peak' newly begin to appear near edge separatrix X-points with increase in density in addition to ordinary edge peaks. The X-point peaks become very clear at high-density range (⩾6 × 1013 cm−3). The C3+ ions analyzed with three-dimensional edge plasma transport code, EMC3–EIRENE, move upstream at low density due to large thermal force. The widely expanded C3+ distribution makes the C IV profile flat. With increasing the density, the friction force becomes dominant and the impurity ions start to move downstream. The C3+ ions stay in the vicinity of the edge X-point where magnetic field lines are very short. The X-point peaks are then clearly formed with increase in the C3+ density. Two-dimensional C IV distribution is also observed for different plasma axis positions. It is found that the C IV emission becomes strong along the poloidal trajectory of X-points and the C IV poloidal trace moves from inboard to outboard X-point trajectories when the plasma axis is changed from 3.60 to 3.75 m. The three-dimensional simulation can well reproduce the enhancement of C IV trajectory along the X-point. However, a discrepancy with the experiment is still seen in the C IV intensity between inboard and outboard X-points.