In this study, we evaluated visual fatigue induced by watching an artificial three-dimensional image with vertical parallax. In the experiment, fifteen subjects completed a task that involved viewing three-dimensional images with four different vertical parallactic angles: 0.0, 0.4,0.6, and 0.8 deg. Visual fatigue was evaluated based on a simulator sickness questionnaire and a critical flicker frequency test. Experimental results showed that the scores of the simulator sickness questionnaire progressively increased with an increase in the vertical parallactic angle, except in Nausea, and the critical flicker frequency decreased the most after watching the three-dimensional image with a vertical parallactic angle of 0.6 deg. These results indicate that a visual fatigue was induced by viewing a stereoscopic image with vertical parallax.