A mold for production of cast parts, having two mold parts in the form of mold plates, which mold parts arc movable with respect to each other from an open position into a closed position, wherein the mold parts in their closed position define a mold cavity which may be filled with liquid casting compound and in their open position enable removal of a cast part which has solidified by at least partial cooling, and are lockable in their closed position by a locking device which joining the two mold parts so as to be releasable, and which mold parts may also be swung, wherewith in the closed position the locking device produces the locking of the mold plates with the stipulation that the locking pressure is maintained. The locking device has an energy storage means with a gas pressure spring for maintaining the closing pressure which presses the mold plates together after they have initially been pressed together.