An oil aerosol has a can member and a compressing member. The can member has a covering part coupled to a can body. The compressing member has a holding tube fitted to the covering part, and received in the can body. A cap is movably disposed in, and has airtight connection with, the holding tube with an elastic member disposed on the bottom to bias same upwards. When the cap is moved up and down by depressing and releasing depressing element placed on the top of the cap, air will be forced into the can member through vent holes of both the cap and the holding tube to increase air pressure in the can member, permitting oil to be dispersed to outside through a nozzle when depressed; both the cap and the holding tube have non-return valves for permitting air to flow only in the above direction into the can member.