The imaging spectroscopic observations of the Magellanic irregular galaxy NGC 4449 were made to show the detailed kinematic structure of the galaxy. Many filamentary structures and Several bubble-like structures are recognized in a 3D data cube of H$\alpha$ 수식 이미지 emission line. Velocity field shows the kpc-scale mosaic structure and counter- rotation of ionized gas.

We show that the star formation activity of spiral galaxies has a great variety. The star formation variation in a time scale of 10 8 yr and the mechanism responsible for the variation are discussed.