To provide an intramedullary nail capable of adjusting the fixing force by operation without requiring a complicated structure for fixing a bone screw in an intramedullary nail body, and allowing surgery to be easily performed with high operability thereof.

An opening 121c corresponding to a horizontal hole 115 is disposed in an engagement member 121 disposed within a shaft hole 113 of the intramedullary nail body which includes the shaft hole 113 and the horizontal holes 114 and 115. The opening 121c has a shape of opening, extended in the direction of an axis 100X longer than the shape of opening of the horizontal hole 115. An inclined edge inclined relative to the axis 100X is formed in the inner side edge on one side of the opening 121c. When the engagement member 121 is moved along the axis 100X, an abutting point of the inclined edge abutting on an insertion part of the bone screw is relatively moved to the opposite side on a side, and the insertion part receives the compression force between the inner side edge on the one side of the opening 121c and the inner side edge on the opposite side of the horizontal hole 115, or the compression force is increased according to the inclination of the inclined edge.