This paper aims to establish a novel VR system for evaluating the performance of baseball batters. Existing VR systems for sports have been utilized as a tool for image training. In order to move such VR systems to the next stage, we introduce functions that sense the users' reaction to the VR stimulus. Our VR system has three features; (a) it synthesizes highly realistic VR video from the data captured in actual games, (b) it estimates the reaction of the user to the VR stimulus by capturing the 3D positions of full body parts, and (c) it consists of off-the-shelf devices and is easy to use. Our demonstration provides users with a chance to experience our VR system and give them some quick feedback by visualizing the estimated 3D positions of their body parts.