PURPOSE: To prevent wrong selection of input key functions for a user by providing a light emitting element which emits light in response to the pushing state of a function selection key as well as to the function of the key which is under selection.

CONSTITUTION: Characters and marks are written to the tops of character keys, and light emitting elements B1WB4 are buried into key main bodies. Then characters and marks are selected and displayed with glowing of those light emitting elements. The elements B1WB4 correspond to areas C1WC4 respectively. Only the area C1 glows when keys S1 and S2 are not pushed to show that only numeric characters are presently selected. When the shift key S2 is pushed, the contact of a switch 2 is changed to 22 from 21. Thus the element B1 is turned off with the element B2 turned on, and only a mark of "projected parallels" of the key top area C2 glows. In the same way, the contact of a switch 1 is changed to 12 from 11 with push of KANA lock key S1. Then the element B3 emits light to display the character key area C3. The contact of a switch 3 is changed to 32 from 31, and the element B3 is turned off with the element B4 turned on.