PURPOSE: To attain high efficiency of transfer control and production management by holding on standby a vehicle to which wrong coating is made or a vehicle to which parts are not supplied at the time of assembly after transferring it to a specified lane, and performing carrying-out after adjusting the transfer sequence of each vehicle.

CONSTITUTION: There is provided a judgement means for judging whether a transfer means carrying a normally painted workpiece is stored in the fore end on the carrying-out side of transfer sequence adjustment lane or a transfer means carrying workpiece to which no parts are supplied or a workpiece to which defective painting is carried out is stored therein. A transfer control means returns the transfer means to a return line when it is judged that the transfer means 30 carrying a normally painted workpiece or the transfer means carrying a workpiece to which no parts are supplied is at the fore end of carrying-out side of transfer sequence adjusting lane. When it is judged that the transfer means 30 carrying a normally painted workpiece is at the fore end thereof, the transfer means is carries out to a post process and subjected to the transfer sequence adjustment. It is thus possible to attain high efficiency of various works of assembling vehicles in the post process.