To improve the operability of housing and taking out a jack.

While a jack 9 is turned upside down, a jack head 11 is mounted on a rear floor panel 1 and a jack bottom 10 is pressure contacted to be fixed against a jack bracket 5 disposed jointedly on the side edge 3 of a trunk room 4. The jack bracket 5 has on the side edge of the longitudinal central part a notch part 6 formed longer than the side edge of the expanded width seat surface part 10b of the jack bottom 10 and formed between the notch and the side edge of the narrowed width seat surface part 10a with an opening part 14 and holding pieces 7, 7 overlaid on the expanded width part 10b of the seat surface on both sides of the notch. If the jack 9 is displaced somewhat sideways, one side edge of the expanded width part 10b of the seat surface is located in the notch part 6 and the other side edge of the expanded width part 10b gets out of the holding piece 7 sideways, so that the jack 9 can be taken out upward as it is.