The invention belongs to the security inspection technological field and provides an infrared detection device. The infrared detection device comprises a transmit-receive light source group; the transmit-receive light source group comprises a first infrared emission light source, a second infrared emission light source opposite to the first infrared emission light source, a first receiving assembly which is disposed at the same side with the second infrared emission light source and is used for receiving light source signals emitted by the first infrared emission light source, and a second receiving assembly which is disposed at the same side with the first infrared emission light source and is used for receiving light source signals emitted by the second infrared emission light source; and the first infrared emission light source sends light of a first predetermined angle to the first receiving assembly; and the second infrared emission light source emits light of a second predetermined angle to the second receiving assembly. The invention further provides a security inspection machine, a security inspection channel and a mechanical apparatus which separately include the above theinfrared detection device. The infrared detection device, security inspection machine, security inspection channel and mechanical apparatus provided by the invention have the advantages of wide effective irradiation area, high detection accuracy, and little possibility of omitted detection and increased inspection.