Abstract: A breath analyzer includes an analyzer body and an alcohol sensor module detachably attached to the analyzer body. The analyzer body includes a signal processing unit for calculating an alcohol concentration, a display unit for displaying the alcohol concentration, a connector coupling unit connected to the signal processing unit and a breath passage conduit. The alcohol sensor module includes an alcohol sensor. The alcohol sensor includes a sample gas passage and a reaction cell arranged within the sample gas passage to output an actual detection signal value corresponding to an alcohol concentration in a sample gas. The sample gas passage is composed of a sample gas inlet tube, a sample gas outlet tube and a sample gas chamber.