Gas detection device

The invention discloses a gas detection device which comprises a shell, a circuit board and a detection unit, at least part of the circuit board and at least part of the detection unit are located in the shell, and the detection unit is installed on the circuit board; the detection unit comprises a detection shell, a light source module and a detection probe, the light source module is arranged at one end of the detection shell in the length direction and used for emitting light, and the detection probe is arranged at the other end of the detection shell in the length direction and used for receiving light; the light source module and the detection probe are electrically connected with the circuit board respectively; a first straight line and a second straight line are defined on a plane perpendicular to the height direction of the gas detection device; the detection shell has a first projection on the plane, and the first straight line extends along the length direction of the first projection; the second st