To clarify the characteristics of the discharge induction against the delay time of impulse application with a long gap/1/, the electron and neutral particle density in the plasma were measured. The electron density was about 1023m−3at 10 &mgr;s after firing the laser and then gradually decreases in several tens of microseconds. The rarefied air region of lower neutral particle density takes a spherical shell profile in later stages after firing the laser. From the experiments of the laser‐induced discharge, it seems that the discharge induction was greatly influenced by the electron attachment to oxygen molecules and rarefied region of the neutral particle density. ©1996 American Institute of Physics.