To provide an on-vehicle jack capable of eliminating the complicated molding process of a housing and complicated welding process, efficiently performing the molding and assembly processes, manufacturing the housing at low cost and reasonably, and performing the surface processing such as the rust prevention easily and precisely for improving the life and the strength, to be operated by a rotary handle smoothly and easily.

The jack has a cylindrical housing 3 erected on a base board 1, a ram guide 45 telescopically mounted inside the housing 3, and a ram 47 telescopically mounted inside the ram guide 45. A shaft cylinder part 4 is made to project on the peripheral surface of the housing 3. The on-vehicle jack is a telescopic jack with a drive gear 32 rotatably supported inside the shaft cylinder part 4. The housing 3 is vertically divided into plural housing pieces 6 and 7. The both sides of the housing pieces 6 and 7, adjacent to each other, are mechanically jointed.