In order to understand the effect of temperature on slug properties, the onset velocity of slugging and slug properties(slug rising velocity, slug length, slug frequency) have been measured with variations of gas velocity and temperature in a electrically heated gas fluidized bed(0.1 m i.d., 2.1 m height, 12 kw). Air was used as fluidizing gas and FCC particle(specific surface mean diameter: 0.071 mm, apparent density: 1,600 kg/m3) as bed material. The gas velocity was varied from minimum fluidizing velocity to 0.15 m/s and the bed temperature from 25 ℃ to 400 ℃. The bubble or slug properties were measured with the differential pressure method using two differential pressure transducers connected with a couple of adjacent pressure taps, respectively. As the bed temperature increased, the minimum slugging velocity, slug rising velocity, and slug length increased whereas the slug frequency decreased. A correlation for the slug rising velocity, which expresses the effect of bed temperature, was proposed.