A cutting insert of one aspect includes a main body section and a cutting section located at least at the front end side of the main body section, wherein the cutting section includes a top surface and a front cutting edge disposed along a ridge line at an intersection between the top surface and a front side surface, the front cutting edge includes a first section, a second section, and a third section, and a portion of the second section is located above the first section and the third section.The front side surface includes a first region located below the first section, a second region located below the second site, and a third regions located below the third site, wherein an angle of inclination of the second region is greater than angles of inclination of the first region and the third region.