An input device for a transmission includes, a knob with which an operator performs rotation and press operations, a rotation detector for detecting that the knob is rotated, a press detector for detecting that the knob is pressed, and a controller for performing, based on results of detection by the rotation detector and the press detector, a range shift between a first forward travel range where a gear shift operation performed by the operator is not accepted and a second forward travel range where the gear shift operation is accepted, and for performing a gear shift in the second forward travel range.