A sampling device provided with: a housing having a main flow channel that comprises a liquid inflow channel and a liquid outflow channel, and a sampling flow channel that branches from a branching part provided between the liquid inflow channel and the liquid outflow channel, one end of the sampling channel being formed as an open end a cap for covering the open end part of the sampling flow channel, the cap being detachable from the housing and a valve provided in an urged state so as to cut off the sampling flow channel from the main flow channel, the sampling flow channel and the main flow channel being no longer cut off when the cap is attached to the housing or when the cap is removed from the housing and a liquid sampling means is attached to the open end part of the sampling channel. The sampling device is characterized in that a venturi unit is provided to the liquid outflow channel and, when the cap is attached to the housing, a bypass channel for interconnecting the inside of the cap and a throat part of the venturi unit is formed. This sampling device prevents liquid from accumulating in the sampling flow channel and allows the sampling region and the surrounding area to be kept at an optimal degree of cleanliness.
