To provide a method and apparatus for hydroforming which can easily form a deep profile.

In the hydroforming method, two metal sheets 2, 20 overlapping one another are pinched by an upper die 11 and a lower die 12, and high-pressure water 3 is injected applying inner pressure between the two metal sheets 2, 20 so that the metal sheets 2, 20 are formed into the profile along the cavities 111, 121 enclosed by the upper die 11 and the lower die 12. When the inner pressure is applied between the 2 pieces of metal sheets 2, 20, at least a portion of a peripheral edge 21 of the metal sheets 2, 20 is pushed in toward the cavities 111, 121.