The increase of backscattered light from the stratospheric aerosol layer was measured by laser radar at Nagoya during the period from the end of April to early July, 1982. On the basis of much information (e.g., SEAN Bull., 1982), this is certainly due to the volcanic eruptions of Mt. El Chichon (Mexico) in March and April 1982. The effect of the Mt. El Chichon eruption on the stratospheric aerosol layer is longer lasting than that of Mt. St. Helens (Washington, USA) in May of 1980.