In a cutting insert according to an embodiment of the present invention, an upper surface includes: a first concave groove which is continuous with a first cutting edge and extends along a longitudinal direction; a pair of second concave grooves which are respectively continuous with a pair of second cutting edges and extend along the longitudinal direction; and a pair of protruded parts respectively located between the first concave groove and the pair of second concave grooves. The pair of protruded parts are respectively continuous with an end surface cutting edge and are separated from each other by a larger distance therebetween as separating from the end surface cutting edge. A cutting tool with the cutting insert, and a method of manufacturing a machined product by using the cutting tool are also provided.