Reaction force controlling apparatus and reaction force controlling system

A reaction force controlling system, comprising:

• a reaction force controlling apparatus that includes
• a first deformable body that includes a first space inside of the first deformable body, the first space having a variable volume,
• a base that includes
• a second space that communicates with the first space through a circulation hole, and
• a third space that does not communicate with the first space or the second space,
• a second deformable body that separates the second space from the third space, the second deformable body being deformed to change the opening area of the circulation hole, the deformation being performed due to fluid flowing into the third space or flowing out of the third space, and
• a first fluid control mechanism that causes the fluid to flow into the third space, and that causes the fluid to flow out of the third space;
• and
• a controller that controls the first fluid control mechanism to adjust an internal pressure in the third space.