Nozzle standby device, liquid processing apparatus and operation method of liquid processing apparatus

A nozzle standby device configured to allow a nozzle to stand by therein includes a nozzle accommodation unit, having an inner circumferential surface formed to surround a leading end portion of the nozzle, provided with a drain opening facing a discharge opening of the nozzle; and a solvent discharge opening opened within the nozzle accommodation unit. The nozzle accommodation unit has a diameter reducing portion having a first and a second inner circumferential surfaces having different angles with respect to a center line of the nozzle accommodation unit such that an inner diameter of the diameter reducing portion becomes smaller toward the drain opening. An intersection point of two straight lines extending along two opposite portions of the first inner circumferential surface is located above the discharge opening of the nozzle when the leading end portion of the nozzle is placed in the diameter reducing portion.