A substrate processing apparatus includes a first drying unit configured to perform a first drying process using a drying fluid on a substrate having a liquid film formed thereon, a first fluid supply unit configured to supply the drying fluid into the first drying unit, a second drying unit configured to perform a second drying process using the drying fluid on the substrate on which the first drying process is performed, a second fluid supply unit configured to supply the drying fluid into the second drying unit, a first door configured to control opening and closing of the first drying unit, and a second door configured to control opening and closing of the second drying unit, wherein the first door is opened when pressure in the first drying unit reaches a first transfer pressure, and the second door is opened when pressure in the second drying unit reaches a second transfer pressure.

A substrate processing system includes: a batch-type processing part that collectively processes a lot including substrates arranged at a first pitch; a single-substrate-type processing part that processes the substrates of the lot one by one; and an interface part that delivers the substrates between the batch-type processing part and the single-substrate-type processing part. The batch-type processing part includes a processing bath that stores a processing solution having a lump shape or a mist shape, a first holder that holds the substrates arranged at the first pitch, and a second holder that receives the substrates arranged at a second pitch from the first holder in the processing solution. The interface part includes a transfer part that transfers the substrates held separately by the first and second holders in the processing solution, from the batch-type processing part to the single-substrate-type processing part.