INPUT DEVICE FOR INPUTTING PASSWORD OR THE LIKE AND MOBILE TELEPHONE HAVING THE INPUT DEVICE

A contact sensor capable of inputting a character by tracing a character with user's finger is arranged in a region of a ten-key unit of a mobile telephone. When registering a password to release a key lock, a user traces a shape of a line, a character, a number, or other symbol on the contact sensor with his/her finger so that the shape is inputted and stored in a memory, thereby completing registration of a password. When releasing the key lock, the user traces the registered shape on the contact sensor with his/her finger so that the key lock is released. The input is easy. Even if the password input operation is observed by a third person, the password will not be easily known to the third person.