Cutting unit, cutting tool, cutting tool rest, and method for manufacturing cut article

A cutting unit comprising:

• a holder having a quadrangular prism shape extending from a front end toward a rear end, and comprising
• a front end surface located on a side of the front end,
• an upper surface extending from the front end surface toward the rear end,
• a lower surface located on a side opposite to the upper surface,
• a first side surface located between the upper surface and the lower surface and extending from the front end surface toward the rear end, and
• a second side surface located on a side opposite to the first side surface;
• a cutting edge located on a side of the front end and the first side surface;
• a holding block comprising a groove which is configured to hold the holder and comprises a first and second inner surface;
• and
• a clamp member
• located at the holding block,
• comprising a pressing portion configured to press the holder toward a side of another inner side surface of the groove in a state of being interposed between the second inner side surface of the groove and the upper surface, and
• configured to fix the holder to the holding block,
• wherein
• the upper surface comprises
• a first cutout comprising a first inclined surface being separated from the lower surface as closer to the rear end, and
• a second cutout located closer to the rear end than the first cutout, and comprising a second inclined surface being separated from the lower surface as closer to the rear end, and
• the pressing portion comprises
• a first protrusion configured to be in contact with the first inclined surface, and
• a second protrusion separated from the first protrusion and configured to be in contact with the second inclined surface.