An electronic ink cartridge includes, in a direction of a central axis within a cylindrical body, a core body extended out from a distal end of the cylindrical body, a coupling member disposed on a side of a proximal end of the cylindrical body, a coil housed between the core body and the coupling member and having a predetermined inductance, and a pressure sensitive element whose capacitance changes according to pressure applied to the core body. Two terminals of the coil are electrically connected respectively to two terminals of the pressure sensitive element to thereby form two terminals of a resonance circuit formed by the coil and the pressure sensitive element. A connecting terminal electrically connected to at least one of the two terminals of the resonance circuit is disposed on a proximal end surface side of the coupling member to be accessible thereon from outside.