An input pen comprising: a wood shaft , a mounting hole that is formed at an axial center of the wood shaft , and an input body that is rod-shaped and is mounted in the mounting hole , wherein an inner side surface of the mounting hole and an outer side surface of the input body are removably fixed, wherein the input body comprises an outer tube , a digitizer unit built-into the interior of the outer tube , a rod-shaped ferrite core that is positioned at an axial center, an electromagnetic induction coil that is disposed at an outer periphery of the ferrite core , wherein the digitizer unit has a structure in which the rod-shaped ferrite core is mounted via a distal end coupling to the distal end of an accommodating tube , a contacting distal tip that is fixed to a distal end of the ferrite core , and a writing pressure sensing portion in accordance with a variable capacitance capacitor that senses pressing force applied to the contacting distal tip , wherein the writing pressure sensing portion is mounted to the rear end of the accommodating tube , wherein the input body is configured as a refill and further comprises a second capacitor , wherein the ferrite core , the electromagnetic induction coil , the writing pressure sensing section and the second capacitor are electronic parts that are built-in within the input body , and form a parallel resonance circuit, wherein: the input body is accommodated in the mounting hole , an insertion restricting portion , which demarcates an insertion limit of the input body in the mounting hole , is provided at a midway portion of the wood shaft , and a rear end of the input body is formed as a press-contact portion that press-contacts the insertion restricting portion . a wood shaft , a mounting hole that is formed at an axial center of the wood shaft , and an input body that is rod-shaped and is mounted in the mounting hole , wherein an inner side surface of the mounting hole and an outer side surface of the input body are removably fixed, wherein the input body comprises an outer tube , a digitizer unit built-into the interior of the outer tube , a rod-shaped ferrite core that is positioned at an axial center, an electromagnetic induction coil that is disposed at an outer periphery of the ferrite core , wherein the digitizer unit has a structure in which the rod-shaped ferrite core is mounted via a distal end coupling to the distal end of an accommodating tube , a contacting distal tip that is fixed to a distal end of the ferrite core , and a writing pressure sensing portion in accordance with a variable capacitance capacitor that senses pressing force applied to the contacting distal tip , wherein the writing pressure sensing portion is mounted to the rear end of the accommodating tube , wherein the input body is configured as a refill and further comprises a second capacitor , wherein the ferrite core , the electromagnetic induction coil , the writing pressure sensing section and the second capacitor are electronic parts that are built-in within the input body , and form a parallel resonance circuit, wherein: the input body is accommodated in the mounting hole , an insertion restricting portion , which demarcates an insertion limit of the input body in the mounting hole , is provided at a midway portion of the wood shaft , and a rear end of the input body is formed as a press-contact portion that press-contacts the insertion restricting portion . the input body is accommodated in the mounting hole , an insertion restricting portion , which demarcates an insertion limit of the input body in the mounting hole , is provided at a midway portion of the wood shaft , and a rear end of the input body is formed as a press-contact portion that press-contacts the insertion restricting portion . <EOS>