Abstract: A mobile virus prevention apparatus is provided. The mobile virus prevention apparatus can execute a vaccine program and be detachably mounted on a host connected to a network. The apparatus includes a first storage area for storing the vaccine program, the vaccine program having a binary format; and a second storage area for sending the vaccine program to the host when the apparatus is connected to the host, and storing an automatic execution file for automatically executing the sent vaccine program, the second storage area being set as a read only area, wherein the vaccine program sends the binary vaccine program to the host when the apparatus is connected to the host, and the sent vaccine program is recomposed as a file format and installed in the host. With the mobile virus prevention apparatus, it is possible to execute a vaccine program for virus prevention independently of an operating system and to install the vaccine program with minimized virus effects.