The present invention provides a machine tool provided with a cover body having a simple structure, excellent operability, and low manufacturing cost. A tool post movement region one-side-closing cover part (9) for closing a tool post movement region open part (8) is configured so as to be: capable of expanding and contracting in a horizontal movement direction of a tool post (3); arranged facing the tool post (3); elongated by urging means (10) to press against the tool post (3) in a relatively slidable manner and close the tool post movement region open part (8); expanded and contracted by movement of the tool post (3) to hold the tool post movement region open part (8) in a closed state; and provided unconnected to the tool post (3) so that the tool post (3) is relatively slidable with respect to the tool post movement region open part (8) is held in a closed state.