A remote control transmitter is capable of controlling a plurality of light fittings without the need for a slidable switch. The remote control transmitter includes a memory for storing data representing a plurality of control signals for respective channels corresponding respectively to the light fittings, a measurer for calculating a period of time during which the operation button is pressed based on a detected event starting when the operation button is pressed and ending when the operation button is released, and outputting a signal representing the calculated period of time, a transmitter for outputting a control signal based on the data stored in the memory, and a controller for setting one of the channels based on the signal output from the measurer, and controlling the transmitter to output a control signal based on the data stored in the memory in association with the set channel.