An electronic pen is provided that is enhanced in strength such as not to be bent or broken even when made to be thinner (smaller in diametric size). A connection section holds a core body at one end thereof and holds a circuit board at the other end thereof. The circuit board is accommodated in a board protecting pipe, which is fitted to the connection section. The board protecting pipe is provided with a side opening, and an operation on an electronic part on the circuit board accommodated therein and a work on an electronic circuit formed on the circuit board can be performed through the side opening. An electronic pen main body section wherein the core body and the circuit board and the board protecting pipe are united together through the connection section is accommodated in a casing, to constitute the electronic pen.