Discharge and sintering phenomena are investigated by measuring current and voltage in pulsed electric current sintering. Fine Al powders under 10μm in particle size and coarse Al powders over 100μm are used. A BN die and a graphite die are used and a graphite punch is used for each die. With BN die and fine Al powders, no current flows until voltage attains 24V. At this voltage a large current over 600A suddenly flows. Some large pores produced by melting and evaporating are observed in the specimen. Discharge occurs when a BN die is used. This discharge can occur in the range of resistivity 10kΩ-1MΩ. The coarse powders can be sintered without discharge. When fine Al powders are sintered using a graphite die, the current and voltage increase simultaneously at the starting stage of sintering. The current depends on the resistivity of powders. The powder compact is sintered from the surface, and then the center region is sintered later. A current almost flows through the graphite die except for fine Al powders. The coarse Al powders can be sintered homogeneously because of current flows through the powders. No discharge occurs with graphite die, and the temperature rises by joule heating.