WORKING MACHINE WITH CRAWLER UNIT

The present invention makes it possible to mount a reinforcement rib along the center of the longitudinal lower part of a fitting section to thereby prevent uneven distribution of a load from a lowerroller. This crawler crane 100 is provided with: an affixation pin 23-1e for affixing an extension beam 23 at the fitting section 32a of a side frame 32; an affixation pin insertion hole 23-1g formedin the extension beam 23; an affixation pin fitting hole 32d formed in the fitting section; and a reinforcement rib 32e extended along the lower surface of the lower plate 32b of the fitting section 32a, and the crawler crane 100 is configured such that the extension beam 23 is affixed to the fitting section 32a by inserting the affixation pin 23-1e into the affixation pin fitting hole 32d throughthe affixation pin insertion hole 23-1g. The reinforcement rib 32e is provided along an imaginary centerline 51 extending from the center of the opening of the fitting section 32a, and the affixationpin fitting hole 32d is pro