Electronic pen and electronic pen main unit

An electronic pen, comprising:

• a tubular casing including an opening at one end side of the electronic pen in an axial center direction that is a pen tip side;
• a fitting part including a joining connector having a plurality of contact terminals;
• and
• an electronic pen main unit configured as a replaceable cartridge in the tubular casing, a rear end part side of the electronic pen main unit on a side opposite from the pen tip side being coupled to the fitting part, the electronic pen main unit including:
• a pen tip part including an electrically-conductive core body configured to protrude externally from the tubular casing through the opening;
• a main body tubular part to which the pen tip part is joined on the pen tip side in the axial center direction, the main body tubular part housing an electronic circuit including a signal generating circuit configured to generate a signal to be transmitted by the core body, and
• a rear-end-part connector that is positioned at a rear end part of the main body tubular part on a side opposite from the pen tip part in the axial center direction, includes a plurality of terminals arranged at a plurality of different locations along the axial center direction of the replaceable cartridge and electrically insulated from each other and electrically connected to the electronic circuit, and is configured to be joined to the joining connector,
• wherein the plurality of terminals are configured to be electrically coupled to the plurality of contact terminals when the replaceable cartridge is received in the tubular casing and the rear-end-part connector is joined to the joining connector, and at least one of the plurality of terminals is a power-supply terminal configured to be electrically coupled to one of the contact terminals to supply power from a power source to the electronic circuit of the replaceable cartridge.