Cometary pickup protons were observed as far as 9.7 × 10⁶ km away from the cometary nucleus, while the pickup cometary ions of water‐group (expected to be mainly O⁺) were observed as far as 4.0 × 10⁶ km. Observation of these cometary ions is based on the identification of a specific feature in the phase space distribution of ions (ion‐pickup shell). We found that the pickup shell is usually filled only partially (∼50%). This observation suggests that the efficiency of the energy diffusion is comparable to that of the pitch angle diffusion. From the spatial asymmetry in the cometary ion density observed between inbound and outbound parts of the spacecraft orbit, it is suggested that there was a difference of a factor of 2‐3 between the ion production rates around the inbound and outbound orbit.