Feeding behaviour of the Japanese pygmy cuttlefish Idiosepius paradoxus, inhabiting sea grass beds, was observed in captivity. Pygmy cuttlefish preferred to feed on crustaceans and the feeding behaviour consisted of two phases, namely, attacking and eating. The sequence of attacking behaviour is divisible into three stages, namely attention, positioning and seizure. In the eating process, pygmy cuttlefish insert buccal mass into the exoskeleton of the captured crustacean. In this action the buccal mass elongates to a similar length to the first arm, and moves in various directions inside the exoskeleton and flesh is ingested as this behaviour proceeds. As a result, the empty exoskeleton remained intact when the pygmy cuttlefish finished feeding.