A vapor-phase process apparatus and a vapor-phase process method capable of satisfactorily maintaining quality of processes even when different types of processes are performed are obtained. A vapor-phase process apparatus includes a process chamber, gas supply ports serving as a plurality of gas introduction portions, and a gas supply portion (a gas supply member, a pipe, a flow rate control device, a pipe, and a buffer chamber). The process chamber allows flow of a reaction gas therein. The plurality of gas supply ports are formed in a wall surface (upper wall) of the process chamber along a direction of flow of the reaction gas. The gas supply portion can supply a gas into the process chamber at a different flow rate from each of one gas supply port and another gas supply port different from that one gas supply port among the plurality of gas supply ports.