A liquid droplet jetting apparatus includes a nozzle which jet the liquid droplets in a plurality of types of jetting modes; a liquid droplet jetting head which has the nozzles; a signal generating section which generates a plurality of types of jetting signals, each of which is formed of bit data, has predetermined bits not less than three bits, and corresponds to one of the plurality of types of jetting modes; and a signal supply section which outputs serially the bit data forming one of the jetting signals to the liquid droplet jetting head at each of jetting timings of the nozzle. The jetting signals are set such that the jetting signals corresponding to the jetting modes respectively are subjected to binary switching of the bit data at frequencies decreasing proportional to usage frequencies of the jetting modes when the bit data are outputted serially from the signal supply section.