Machine tool having tool rest, control unit, tool storage unit, tool changing unit, and tool management unit

A machine tool comprising:

• a tool rest including:
• (i) a plurality of first holders each configured to allow a respective shank portion of a respective tool to be inserted thereinto in a first direction to hold the respective tool, and (ii) a plurality of second holders each configured to allow a respective shank portion of a respective tool to be inserted thereinto in a second direction different from the first direction to hold the respective tool;
• a machining control unit configured to control a tool held by the tool rest to machine a workpiece in accordance with a machining program;
• a tool storage unit capable of storing a plurality of tools therein;
• a tool changing unit configured to change one of the tools held by the tool rest with one of the tools stored in the tool storage unit;
• and
• a tool management unit configured to identify an unusable tool in the tools stored in the tool storage unit, the unusable tool being a tool that cannot be used to perform machining, wherein
• in a case where the machining program utilizes a plurality of tools of a same first type, which plurality of tools of the first type includes tools that are to be attached to ones of the first holders, and which plurality of tools of the first type also includes a tool that is to be attached to a respective one of the second holders, and when the tools of the first type include the unusable tool and, when the ones of the first holders and the one of the second holders to which the tools of the first type are to be attached have a quantity of the first holders that is larger than a quantity of the second holders, machining control unit causes the tool changing unit to attach the unusable tool to one of the first holders.