Coupling device

A coupling device comprising:

• a first joint;
• a second joint detachably connected to the first joint;
• a first supply/discharge passage provided in the first joint;
• a second supply/discharge passage provided in the second joint and detachably connected to the first supply/discharge passage;
• a sub valve chamber and a main valve chamber formed so as to be continuous from a distal end side to a proximal side in an axial direction in the second joint;
• a sub valve member inserted into the sub valve chamber so as to be movable in the axial direction via a sealing member in a sealed manner, urged to the distal end side toward a sub valve seat formed in the sub valve chamber by a sub valve member closing spring, and having a sub valve surface capable of coming into contact with the sub valve seat;
• and
• a main valve member inserted into the main valve chamber so as to be movable in the axial direction in a sealed manner, capable of coming into contact with the sub valve member, and urged to a distal end side toward the main valve seat formed in the main valve chamber by a main valve member closing spring,
• wherein a communication path is formed in the sub valve member as a part of the second supply/discharge passage, and a filter is mounted so that at least a portion of said filter is disposed in a middle of the communication path.