A cutting device includes a cutting unit having a rotary blade, a table for placing a workpiece thereon, and a support device vertically movably supporting the cutting unit relative to the table. The cutting unit includes a blade case. The blade case covers an upper portion of the rotary blade and has a dust discharge member for discharging dust produced at a cutting region. The cutting device further includes a dust guide device disposed on at least one of an upstream side and a downstream side of the dust discharge member with respect to a flow of the dust. A position of at least a part of the dust guide device changes relative to the dust discharge member according to change of the vertical position of the cutting unit.