To uniformly eject a magnetic coating material in a width direction of a slit and thereby to prevent generation of coating stripes.

An applying device has a coating material supplying means for supplying the magnetic coating material, a liquid pool part to which the magnetic coating material is supplied from the coating material supplying means and a pair of lips which are connected with the liquid pool part and are disposed to face each other at a prescribed space. Further the applying device is provided with a dye head which applies the magnetic coating material ejected from a space formed by a pair of lips onto a body to be coated and a magnetic field generating means disposed at a position facing the lips via the body to be coated. Further at least top end parts of a pair of lips are made of precipitation hardened stainless steel.