A steam cooking apparatus, comprising drain means (drain pipe, drain valve (54)) for draining water in a pot. A control device (80) drains the water in the pot by the drain means when either of such requirements that [1] a retention time timed by a first timing part (101a) reaches a specified time, [2] a cumulative time from the start of water supply timed by a second timing part (101b) reaches aspecified time, [3] an overall water supply amount to the pot detected by a water supply amount detection part (102) reaches a specified volume, [4] an overall time for water supply to the pot timed by a third timing part (101c) reaches a specified time, and [5] an instruction for water drain is inputted by an operation panel (13) is satisfied. Accordingly, the inside of a steam generating means can be maintained in a sanitary state by avoiding the decay of the water remaining in a steam generating device (pot) while reducing water consumption and a load on a user for the supplement of water.