Fix bolt-unfastening preventing structure

Disclosed is a fix bolt-unfastening preventing structure. The fix bolt unfastening structure includes a fix bolt including a head designed to be fitted to a fastener tool, and a body integrally formed with the head, wherein the body has a threaded portion on a circumferential surface thereof and a press fit portion formed at one end thereof; and a fix member having a press fit hole into which the press fit portion is to be press-fitted. According to the present invention as described above, there is an advantage that in order to prevent unfastening of the fix bolt which is used for connection of various components, the fix bolt is threaded engaged with the fix member while the press fit portion formed at the end of the male screw thread of the fix bolt is press-fitted into the press fit hole formed at an end of the fix member, which enables the reduction of parts and cost and the prevention of unfastening of the fix bolt.