The invention relates to a pressing machine for manufacturing of products such as centre plugs for bobbins, pallet blocks, etc., from wood fibre material supplemented with hardenable binder. The pressing machine has a curing chamber (10) with a channel system formed therein, where hollow moulding tools (22) are transported after having been filled with wood fibre material. The distance, in the height direction, between the inner side of the curing chamber's roof and its internal bottom side is adjustable by means of an adjustment device (23), so that said roof's inner side and bottom inner side form closures for the upper and lower parts of the moulding tools and thereby allow replacement of the moulding tool's format, for example for another mould height.