Tool body and cutting tool

A tool body which has at least one insert seat and on which cutting inserts having different shapes are capable of being mounted, wherein:

• the insert seat comprises a bottom wall surface and a side wall surface and has a configuration in which the bottom wall surface or a surface formed by extending the bottom wall surface and the side wall surface or a surface formed by extending the side wall surface intersect with each other;
• the side wall surface comprises a first side wall surface and a second side wall surface;
• the first side wall surface comprises at least two surface portions which are configured to come into contact with a peripheral side surface of the cutting insert depending on a shape of the cutting insert;
• from among the two surface portions, the first surface portion is a curved surface having a recessed shape recessed toward a base end of the tool body, and the second surface portion is a flat surface or a curved surface having a recessed shape recessed toward the base end of the tool body, with a greater curvature radius than that of the first surface portion;
• the tool body has a rotational axis which is defined so as to penetrate the tool body from a leading end to the base end;
• and
• the at least two surface portions are configured so as to be placed from the central axis toward the outer periphery or so as to be placed from the central axis toward the leading end.