There is provided an air atomizing type coating apparatus which is constituted by a main body (2) having a first feed tube passage hole (6) extended forward from a cartridge mount portion (5), a passage change-over mechanism (11) attached to the front side of the main body (2) to change over positions of a second feed tube passage hole (14) and a second wash fluid passage (15), a spray nozzle (22) attached on the front side of the passage change-over mechanism (11), and a paint cartridge (30) to be set in the cartridge mount portion (5). Upon shifting the passage change-over mechanism (11) to a coating position, the first and second feed tube passage holes (6) and (14) are brought into communication with each other, a coating operation can be performed by inserting a paint cartridge (30). On the other hand, upon shifting the passage change-over mechanism (11) to a washing position, the first and second wash fluid passages (9) and (15) are brought into communication with each other, permitting a supply of a wash fluid to the spray nozzle (22).