A conveyance system includes: a travel plan generating unit to generate a travel plan of the conveyance vehicle, the travel plan being used to execute conveyance of the trailer from the parking lot to a platform by the conveyance vehicle or conveyance of the trailer from the platform to the parking lot; and an extraneous vehicle determining unit to determine whether or not the extraneous vehicle is present in the site. When the extraneous vehicle determining unit determines that the extraneous vehicle is present in the site, the travel plan generating unit generates the travel plan in which the conveyance vehicle does not obstruct traveling of the extraneous vehicle. In this case, traveling of the extraneous vehicle such as a truck is not obstructed by the conveyance vehicle, so that operation efficiency of the delivery center can be improved.