Motions of ions in the plasma focus are investigated theoretically using a model for az‐pinch type plasma focus. Macroscopic radial motions of plasma are calculated numerically using the snowplow model, the Leontovich–Osovets’ equation, and a circuit equation. The equations of motion of ions are solved in the presence of fields induced in the pinched phase of the macroscopic motion. It is found that in the collapse phase there appears a betatron‐like acceleration process of ions with negligible drift velocity. It is also shown that a strong free‐streaming acceleration process leading to high, axial velocity of ions in the direction of current flow appears in the expansion phase.