In a treatment liquid supply system that supplies treatment liquid used for coating industrial objects for film formation including a semiconductor substrate, a display substrate, a glass and the like, a nozzle connected to a treatment liquid tank vacuum-sucks and injects the treatment liquid from the treatment liquid tank due to a negative pressure occurring in the nozzle, wherein supply control of a small flow amount of the treatment liquid to the nozzle can be performed due to a difference pressure between pressure in the treatment liquid tank and the negative pressure occurring in the nozzle.