An analysis unit includes a frontal plane to access the analysis unit, a mounting plane perpendicular to the frontal plane, and a gas measurement device. The gas measurement device includes a connection housing part and a main housing part. The connection housing part includes an inlet channel and an outlet channel which extend from the mounting plane to a first connection plane. The main housing part includes a second connection plane which corresponds to the first connection plane. The main housing part rests on the first connection plane. The main housing part further includes an inflow channel which fluidically communicates with the inlet channel via the first connection plane, and a recirculation channel which fluidically communicates with the outlet channel via the first connection plane. The first and second connection planes are tilted at an angle of 45° from the mounting plane in a direction of the frontal plane.