The invention relates to a device (1) for producing three-dimensional workpieces (15), comprising a carrier (7) for receiving raw material powder (9), a build chamber wall (11, 11a, 11b) which extend substantially vertically and which is adapted to laterally delimit and support the raw material powder (9) applied to the carrier (7); an irradiation unit (17) for selectively irradiating the raw material powder (9) applied to the carrier (7) with electromagnetic radiation or particle radiation in order to produce on the carrier (7) a workpiece (15) manufactured from the raw material powder (9) by an additive layer building method, wherein the irradiation unit (17) comprises at least one optical element; and a vertical movement device (31) which is adapted to move the irradiation unit (17) vertically relative to the carrier (7). The build chamber wall (11, 11a, 11b) and the carrier (7) are adapted to be connected to one another in a stationary manner during the vertical movement of the irradiation unit (17) so that the vertical movement takes place relative to the carrier (7) and relative to the build chamber wall (11, 11a, 11b).