Joining structure for flow path member and column attachment/detachment unit

Provided are a joint structure for a flow path member and a column attachment/detachment unit in which a member represented by a column can be easily attached/detached to/from a member represented by a column attachment/detachment unit by a simple structure without using a large number of members due to a complicated structure. The flow path member joining structure enables the flow of a liquid by fitting a second member having a second flow path open at a first end surface of a first member and fitting the first member to a first member having a first flow path open at a second end surface of the first member, and aligning the first flow path and the second flow path to each other. A diameter-expanded portion having an inner diameter gradually increasing toward the first end surface is formed at an end portion of the first flow path, and the second flow path opens at a second end surface of the second member. 提供不因复杂的构造而使用许多部件、通过简单的构造而由柱代表的构件能够相对于由柱装卸单元代表的构件容易地装卸的流路构件的接合构造及柱装卸单元。流路构件的接合构造通过使具有第二流路的第二构件向具有第一流路