To provide a walking type working machine with which a fuel tank of a large capacity can be equipped while suppressing an increase of a length in the longitudinal direction of a machine body.

In the walking type working machine equipped with a traveling device 1 or a working device via a driving output shaft 10 provided at a lower part of a transmission case 20, an engine 3 and a fitting part 40 of a steering handle 4 are provided at the upper side. A heat insulating plate 5 is provided at a position covering the upper side of the engine 3. A fuel tank 6 and a tank cover 7 for covering the front side of the fuel tank 6 are provided at the upper side of the heat insulating plate 5. Fitting and fixing parts 53, 55B, 57a and 57b to the fuel tank 6 and the tank cover 7 are formed on the heat insulating plate 5.