PROBLEM TO BE SOLVED: To provide a sample gas branching apparatus capable of performing GC-MS/odor smelling analysis, GC-separation and the like freely by only changeover operation without changing the apparatus configuration.SOLUTION: The sample gas branching apparatus comprises: a sample injection port with a pressure controller; a GC column connected to the sample injection port; a three-way connector Tconnected to the GC column; three-way connectors T, Teach connected to the three-way connector T; a three-way connector Tconnected to the three-way connector T; a flow pass changeover valve Vconnected to the three-way connectors T, T, and changing over a flow pass to the three-way connectors T, T; a three-way connector Tconnected to the flow pass changeover valve V; a first pressure controller connected to the three-way connector T; a flow pass opening/closing valve Vconnected between the three-way connectors Tand Tbypassing the flow pass changeover valve V; a first sample gas discharge port connected to the
