A very small film heater immersed in ethyl alcohol, toluene or water is heated at an extremely high rate to a maximum temperature rise of 93 x 10(6) K s-1. The nucleation process is photographed and the temperature at boiling incipience is measured. At a higher heating rate, a large number of tiny bubbles generate concurrently on the heater surface and the temperature at boiling incipience agrees with the homogeneous nucleation temperature for ethyl alcohol and toluene, whereas it is about 19-degrees-C lower for water. The number density of the nucleated bubble is compared with those calculated by the nucleation theory.