Electronic pen and electronic pen body portion

An electronic pen body portion for use in an electronic pen including an outer housing to be grasped by a user and a replaceable electronic pen body portion installed in the outer housing,

• the outer housing including an opening portion provided on a pen-point side of the outer housing to enable installation of the electronic pen body portion, an operation-unit opening portion defined in a side of the outer housing and provided at a position corresponding to a position of a pressing member of the electronic pen body portion when the electronic pen body portion has been installed at a predetermined position, and an operation unit provided in the operation-unit opening portion such that an inside surface of the operation unit which is opposite to the pressing member does not protrude inwardly from an inner wall surface of the outer housing,
• the electronic pen body portion comprising:
• a refill body including a pen point;
• a circuit board having a push button switch mounted thereon;
• a body portion housing that houses the refill body and the circuit board, and has a side opening portion defined in a side of the body portion housing and provided at a position corresponding to a position of the push button switch of the circuit board;
• and
• a pressing member that is provided in the side opening portion of the body portion housing, is disposed on the push button switch, and has an engagement portion that prevents the pressing member from protruding outwardly of a side surface of the body portion housing,
• wherein, when a pressure having at least a predetermined value is applied to the refill body of the electronic pen body portion installed in the outer housing, the electronic pen body portion slides inside the outer housing, and
• wherein, when the electronic pen body portion has been installed in the outer housing, the push button switch is operated through the pressing member as a result of the operation unit of the outer housing being pressed.