A dielectric (16) is housed in a chassis (15) having an opening (22) and a main face portion (23). The dielectric (16) is formed with a hole (30) extending from a first surface (28) to a second surface (29) thereof, and the main face portion (23) of the chassis (15) is formed with a through-hole (25). A conductive pin (17) is inserted into the hole (30) and the through-hole (25) with one end portion thereof projected to the outside of the chassis (15) from the main face portion (23). Further, the electrode portion (32) of the lead electrode (18) is interposed between the second surface (29) of the dielectric (16) and the main face portion (23) of the chassis (15), and a terminal piece (33) of the lead electrode (18) is projected toward the outside from the main face portion (23) of the chassis (15). Further, a conductive elastic member (19) is arranged to approach the first surface (28) of the dielectric (16). Further, a biasing member (21) is provided for biasing the electrode portion (32) of the lead electrode (18) or the dielectric (16), so that the second surface (29) of the dielectric (16) and the electrode portion (32) of the lead electrode (18) are brought into contact with each other. With such a configuration, the dielectric and the electrode can be reliably brought into contact with each other, and good pen pressure characteristics can be obtained.