To provide a user-friendly bottom face cleaning machine set for a vehicle.

This bottom face cleaning machine set includes a cleaning head 1 having a traveling rotating body 10 capable of traveling on a plane under a bottom face of the vehicle and a cleaning means 5 injecting cleaning water toward the bottom face, and a long handle member 2 attaching the cleaning head 1 at a distal end and having both of a pipe function for supplying cleaning water from a grip part 6 at a base end and an operation function for controlling movement of the cleaning head 1. A plurality of kinds of cleaning heads 1A and 1B having different traveling rotating bodies 10 and a plurality of kinds of long handle members 2A and 2B having different shapes are freely combined.