PURPOSE: To efficiently apply ultrafine particles containing no impurities and having high dispersing density, by charging a suspension containing ultrafine solid particles dispersed therein in an aerosol generator and guiding the aerosol generated to an electrostatic gun.

CONSTITUTION: A suspension S having ultrafine solid particles dispersed therein is replenished in the hermetically closed container 2 of an aerosol generator 1 so as to exceed the jet orifice 4 of an air diffusing pipe 3. When a relatively low pressure air CA is supplied to the air diffusing pipe 3 in this state to be injected in the suspension S from the jet orifice 4, said air becomes air bubbles B to rise in the suspension S and said air bubbles B are ejected above the surface of the suspension to burst and the fragments of a membrane are formed into ultrafine particles along with the suspension to be dispersed into the open air above the surface of the suspension. The liquid is evaporated to obtain an aerosol As composed only of ultrafine solid particles and, therefore, said aerosol is applied to the surface of an article A to be coated from a nozzle 8 using an electrostatic gun 7 through corona discharge.