In a steam cooker, a tray-shaped case (51) of a steam temperature-raising device (50) has a recessed part (51a) into which steam from a steam generator flows through steam supply ports (95A, 95B, 95C) provided in a first sidewall (91). The recessed part (51a) has a planar shape roughly symmetrical with respect to a center line (L) of a steam flow entering through the steam supply ports (95A, 95B, and 95C). First and second steam superheaters (52, 53) are placed in the recessed part (51a) of the tray-shaped case (51) so as to be symmetrical with respect to the center line (L). A spiral heat radiation fin (56) having a fin pitch of 10 mm or less is wound around the first steam superheater (52). The tray-shaped case (51) is placed on a ceiling panel of a heating chamber and at steam outlets with an opening of the recessed part (51a) directed downward.