An electronic pen includes: a tubular casing; a rod-shaped core body that projects outside of the casing through an opening of the casing, the opening being formed on one side in axial direction of the casing; a pen pressure detector disposed within a hollow portion of the casing, wherein the pen pressure detector, in operation detects a pen pressure applied to the core body; a core body insertion member disposed between the pen pressure detector and the opening of the casing within the hollow portion of the casing, the core body insertion member housing the core body movably in the axial direction of the casing and having a hollow space closed on a side of the pen pressure detector by a barrier; and a first sealing member that separates the hollow space of the core body insertion member from the hollow portion of the casing.