To prevent misoperation and to improve the operability of a terminal machine by judging an inclination on the operation of a user from an operation history when the user executes a misoperation and an operation history when a precise operation is executed and assisting the operation.

An operation history registration processing part 115 registers operation information showing an operation content which a user executes against a terminal machine as an operation history. A misoperation judgment processing part 116 judges the type of the misoperation recorded in the registered operation history. When the judged type of the misoperation is an operation error, a key operation assist history registration processing part 117 registers the content of the operation error. When the registered input operation is executed again, a key operation assist execution processing part 121 executes an operation assist for emphasizing a use key. When the type of the misoperation is an input error, an input assist history registration processing part 120 registers the content of the input error. When the registered input operation is executed again, an input assist execution processing part 122 assists input for promoting input following an input rule.