The current flow in the plasma was measured by a 1.1 mm diameter magnetic probe inserted directly into the discharge chamber using several types of electrode shapes for a 3 kJ Filippov-type plasma focus apparatus. The current distribution in the plasma sheet was found, unexpectedly, to have two peaks, and the amount of current flow in the plasma at the 'pinch time' varied from 77 to 25% of the total current among the tested electrode shapes which gave very different neutron yield with each other. Thus it was confirmed that main cause of the strong electrode shape effect on the neutron yield found out in the authors 3 kJ Filippov-type plasma focus apparatus was the different magnitude in the plasma current.