A handwriting input device configured to obtain handwritten data of an electronic pen (3, 4) on a coordinate detection surface of a coordinate input device by an electromagnetic induction effect of the coordinate input device and the electronic pen (3, 4), the handwriting input device comprising: the coordinate input device; and the electronic pen (3, 4), wherein the electronic pen (3, 4) includes a resonance circuit including a coil, a capacitor, and a core, a mechanical pencil unit configured to perform writing on a paper sheet placed on the coordinate detection surface, and a writing pressure detecting portion configured to detect a writing pressure such that a part of the mechanical pencil unit is pushed by receiving the writing pressure applied to a lead projecting from a distal end of the mechanical pencil unit, wherein the handwriting input device is configured so that, upon detecting the writing pressure, the coordinate input device obtains the handwritten data corresponding to a handwriting on the paper sheet while writing is performed on the paper sheet with the electronic pen (3, 4), wherein the electronic pen (3, 4) internally includes a lead deliver portion configured to advance and retreat, the lead deliver portion is configured to deliver the lead from the distal end of the mechanical pencil unit, the lead deliver portion is configured to axially retreat together with the lead by receiving the writing pressure in a state where the lead is projecting from the distal end of the mechanical pencil unit, and the writing pressure detecting portion is configured to act in response to a movement of the lead deliver portion with the writing pressure, wherein the electronic pen is configured such that in a non-writing state in which the lead is not housed in a lead case of the mechanical pencil unit, or even if the lead is housed in the lead case of the mechanical pencil unit and the lead does not project from the distal end of the mechanical pencil unit, the lead deliver portion does not retreat and the writing pressure detecting portion does not act, even if the distal end of the mechanical pencil unit is pressed, and wherein a pipe shaped shaft tube is internally and fixedly arranged in the electronic pen (3, 4), the lead deliver portion is inserted into a distal end side of the shaft tube, the lead deliver portion includes a flange opposed to a distal end surface (30a1) of the shaft tube ahead of the distal end surface (30a1), the writing pressure detecting portion is disposed on one of the flange and the distal end surface (30a1), and the writing pressure detecting portion is pushed by the distal end surface (30a1) or the flange to detect the writing pressure. the coordinate input device; and the electronic pen (3, 4), wherein the electronic pen (3, 4) includes a resonance circuit including a coil, a capacitor, and a core, a mechanical pencil unit configured to perform writing on a paper sheet placed on the coordinate detection surface, and a writing pressure detecting portion configured to detect a writing pressure such that a part of the mechanical pencil unit is pushed by receiving the writing pressure applied to a lead projecting from a distal end of the mechanical pencil unit, wherein the handwriting input device is configured so that, upon detecting the writing pressure, the coordinate input device obtains the handwritten data corresponding to a handwriting on the paper sheet while writing is performed on the paper sheet with the electronic pen (3, 4), wherein the electronic pen (3, 4) internally includes a lead deliver portion configured to advance and retreat, the lead deliver portion is configured to deliver the lead from the distal end of the mechanical pencil unit, the lead deliver portion is configured to axially retreat together with the lead by receiving the writing pressure in a state where the lead is projecting from the distal end of the mechanical pencil unit, and the writing pressure detecting portion is configured to act in response to a movement of the lead deliver portion with the writing pressure, wherein the electronic pen is configured such that in a non-writing state in which the lead is not housed in a lead case of the mechanical pencil unit, or even if the lead is housed in the lead case of the mechanical pencil unit and the lead does not project from the distal end of the mechanical pencil unit, the lead deliver portion does not retreat and the writing pressure detecting portion does not act, even if the distal end of the mechanical pencil unit is pressed, and wherein a pipe shaped shaft tube is internally and fixedly arranged in the electronic pen (3, 4), the lead deliver portion is inserted into a distal end side of the shaft tube, the lead deliver portion includes a flange opposed to a distal end surface (30a1) of the shaft tube ahead of the distal end surface (30a1), the writing pressure detecting portion is disposed on one of the flange and the distal end surface (30a1), and the writing pressure detecting portion is pushed by the distal end surface (30a1) or the flange to detect the writing pressure.