A drilling tool comprising: a tool main body configured to be rotated around an axis thereof and to receive a striking force acting toward a tip side thereof in a direction of the axis; and a fitting member including a fitting shaft portion to be inserted into a fitting hole portion which is open in a tip portion of the tool main body so as to be detachably fitted to the tool main body, wherein an outer peripheral surface of the fitting shaft portion has a recessed groove provided along a virtual plane orthogonal to a center line of the fitting shaft portion, a pin hole, which is partially open on an inner peripheral surface of the fitting hole portion by extending from an outer peripheral surface to an inner peripheral side of the tool main body along the virtual plane of the fitting shaft portion inserted into the fitting hole portion, is formed in the tool main body, a locking pin is inserted into the pin hole so as to be locked by the recessed groove of the fitting shaft portion inserted into the fitting hole portion, a fixing member for retaining the locking pin by coming into contact with the locking pin is fitted to an opening portion of the pin hole on the outer peripheral surface of the tool main body, and a locking portion for locking the fixing member in a center line direction of the pin hole is provided in the opening portion, the outer peripheral surface of the tool main body adjacent to the opening portion of the pin hole has a recess which communicates with the opening portion of the pin hole, the recess has an auxiliary member which has a side surface capable of coming into contact with a side surface facing the recess of the fixing member and which maintains a locked state between the fixing member and the locking portion, characterized in that when viewed in the center line direction of the pin hole, a straight line connecting a center of the recess and a center line of the pin hole to each other extends in a direction intersecting the axis. a tool main body configured to be rotated around an axis thereof and to receive a striking force acting toward a tip side thereof in a direction of the axis; and a fitting member including a fitting shaft portion to be inserted into a fitting hole portion which is open in a tip portion of the tool main body so as to be detachably fitted to the tool main body, wherein an outer peripheral surface of the fitting shaft portion has a recessed groove provided along a virtual plane orthogonal to a center line of the fitting shaft portion, a pin hole, which is partially open on an inner peripheral surface of the fitting hole portion by extending from an outer peripheral surface to an inner peripheral side of the tool main body along the virtual plane of the fitting shaft portion inserted into the fitting hole portion, is formed in the tool main body, a locking pin is inserted into the pin hole so as to be locked by the recessed groove of the fitting shaft portion inserted into the fitting hole portion, a fixing member for retaining the locking pin by coming into contact with the locking pin is fitted to an opening portion of the pin hole on the outer peripheral surface of the tool main body, and a locking portion for locking the fixing member in a center line direction of the pin hole is provided in the opening portion, the outer peripheral surface of the tool main body adjacent to the opening portion of the pin hole has a recess which communicates with the opening portion of the pin hole, the recess has an auxiliary member which has a side surface capable of coming into contact with a side surface facing the recess of the fixing member and which maintains a locked state between the fixing member and the locking portion, characterized in that when viewed in the center line direction of the pin hole, a straight line connecting a center of the recess and a center line of the pin hole to each other extends in a direction intersecting the axis.