Tool Rest and Machine Tool

A tool rest includes a plurality of attachment portions to which a plurality of tool holders are detachably attached respectively. Each of the tool holders includes a clamp mechanism for clamping a tool. The attachment portion includes a seat surface on which the tool holder is seated. The tool rest further includes: a first air channel to which air is supplied; a plurality of second air channels branched off from the first air channel and respectively extending toward the plurality of attachment portions, each of the plurality of second air channels being open to the seat surface of a corresponding one of the plurality of attachment portions; and a detector that is provided on a path of the first air channel and detects a state of an airflow.