A portable sterilizer is disclosed. The portable sterilizer is composed of a housing for carrying and a sterilization device such as a UV light or an ozone generator inside the housing. A chamber with certain space is disposed inside the housing, connecting with the sterilization device for being disinfected. An opening is on the housing for putting tableware such as knives, forks, spoons or chopsticks inside the chamber to be sterilized by UV light or ozone gas. Thus users can carry the present invention with them and sterilize tableware or daily essentials easily.