A laser processing device comprising: a laser emission unit configured to emit laser beam; a control member (31, 32) configured to control the laser emission unit; a casing in which the laser emission unit and the control member (31, 32) are accommodated; the laser processing device being characterised by: a pipe through which, in use, compressed gas supplied from outside of the casing flows in a branched manner, the pipe being provided in the casing, wherein the pipe includes a first branch pipe arranged with a leading end for jetting the compressed gas facing the laser emission unit, and a second branch pipe arranged with a leading end for jetting the compressed gas facing the control member (31, 32); a wall provided between the laser emission unit and the control member (31, 32); a first space which is a space formed by partitioning inside the casing by the wall and in which the laser emission unit is arranged; and a second space which is a space formed by partitioning inside the casing by the wall, in which the control member (31, 32) is arranged, and which is in communication with the first space at least on one side in a partitioning direction along which the wall extends, wherein the leading end of the first branch pipe is arranged on the other side in the partitioning direction with respect to the laser emission unit in the first space, and a vent (19, 21) for discharging the gas inside the casing to the outside of the casing is provided in a lateral surface, which is included in a plurality of lateral surfaces constructing the casing and which is positioned on the other side in the partitioning direction. a laser emission unit configured to emit laser beam; a control member (31, 32) configured to control the laser emission unit; a casing in which the laser emission unit and the control member (31, 32) are accommodated; the laser processing device being characterised by: a pipe through which, in use, compressed gas supplied from outside of the casing flows in a branched manner, the pipe being provided in the casing, wherein the pipe includes a first branch pipe arranged with a leading end for jetting the compressed gas facing the laser emission unit, and a second branch pipe arranged with a leading end for jetting the compressed gas facing the control member (31, 32); a wall provided between the laser emission unit and the control member (31, 32); a first space which is a space formed by partitioning inside the casing by the wall and in which the laser emission unit is arranged; and a second space which is a space formed by partitioning inside the casing by the wall, in which the control member (31, 32) is arranged, and which is in communication with the first space at least on one side in a partitioning direction along which the wall extends, wherein the leading end of the first branch pipe is arranged on the other side in the partitioning direction with respect to the laser emission unit in the first space, and a vent (19, 21) for discharging the gas inside the casing to the outside of the casing is provided in a lateral surface, which is included in a plurality of lateral surfaces constructing the casing and which is positioned on the other side in the partitioning direction. a pipe through which, in use, compressed gas supplied from outside of the casing flows in a branched manner, the pipe being provided in the casing, wherein the pipe includes a first branch pipe arranged with a leading end for jetting the compressed gas facing the laser emission unit, and a second branch pipe arranged with a leading end for jetting the compressed gas facing the control member (31, 32); a wall provided between the laser emission unit and the control member (31, 32); a first space which is a space formed by partitioning inside the casing by the wall and in which the laser emission unit is arranged; and a second space which is a space formed by partitioning inside the casing by the wall, in which the control member (31, 32) is arranged, and which is in communication with the first space at least on one side in a partitioning direction along which the wall extends, wherein the leading end of the first branch pipe is arranged on the other side in the partitioning direction with respect to the laser emission unit in the first space, and a vent (19, 21) for discharging the gas inside the casing to the outside of the casing is provided in a lateral surface, which is included in a plurality of lateral surfaces constructing the casing and which is positioned on the other side in the partitioning direction.