PURPOSE: To obtain a baked product having large dough volume, soft texture and soft craft by heating a product dough with steam supplied from a-steam generator.

CONSTITUTION: The oven 1 provided with a steam generator transfers a product dough with an endless belt 7 and bakes the dough in the course of transfer while supplying steam to the dough. The steam generator 11 has a water-channel 10 formed in the longitudinal direction of the endless belt. The water-channel is faced to at least one side part 7b in the moving direction of the belt 7 and inclined from the inlet 3 toward the outlet 4 of the oven. Water is supplied to the water channel 10 from the inlet side 3 and evaporated by the heat in the oven. The remaining water is discharged from the outlet side 4.