To provide a press forming method and device that can suppress a decrease in a plate thickness of a vertical wall and further relatively decrease a plate thickness of a bottom when a component is pressed and formed including a groove having the vertical walls on both sides thereof.

In a press forming method, a heated plate material 3 to be formed is pressed and formed on a component provided with a groove having vertical walls on both sides thereof using a die 5 and a punch 7 which are divided in an expandable manner. The press forming method includes: a step where a part corresponding to a bottom of the groove in the die 3 and the punch 7 pushes the die 3 and the punch 7 so as not to abut against the plate material to be formed; and a step of moving the die 3 and the punch 7 in an expansion direction when the die 3 and the punch 7 move to the bottom dead center while sandwiching the plate material to be formed to extend the bottom in a width direction.