An input apparatus that allows those who are severely physically handicapped for example to enter characters with comparative ease and minimizes the chance of making error entries. The input apparatus comprising: an optical signal transmitter constituted to be worn on the head of an operator and having a plurality of light-emitting elements for transmitting an optical signal and a breath-operated switch; an image display device on which a cursor is shown; and an optical signal receiver connected to the image display device and having a single light-receiving element for receiving the optical signal and a data processor; wherein the optical signal transmitter, when worn on the operator head, transmits, on the optical signal, a data signal containing switch data to be generated when the breath-operated switch is operated, the optical signal receiver generates coordinate data from positional data indicating a shift of the operator head from a predetermined position in the optical signal transmitter and switch data contained in the data signal according to a reception state of the optical signal coming from the optical signal transmitter and supplies the generated coordinate data to the image display device, and the image display device moves a display position of the cursor according to the positional data contained in the coordinate data and selects a display capability according to the switch data contained in the coordinate data.