Flow path forming device

To provide a flow path forming device that substantially makes a compact flow control system, a flow path forming device 100 of the present disclosure includes a carrying panel P1 which includes a carrying surface, the carrying surface being a surface used for mounting a plurality of fluid apparatuses which include at least a mass flow controller M. The carrying panel P1 incudes: a plurality of branch lines L, including a plurality of connecting lines L1 which connect with an entry portal or an exit portal of the fluid apparatuses, and a flow line L2 connecting with the connecting lines L1 to have the fluids flow in the fluid apparatuses; and confluent channels C1, C2, C3, connecting the connecting lines L1 of different branch lines L to converge the flowing fluids of each branch line L; the branch lines L and the confluent channels C1, C2, C3 are voids forming within the carrying panel P1, and the flow line L2 and the confluent channels C1, C2, C3 stereoscopically intercross with each other in the carrying p