To provide a hydraulic control device for a construction machine ensuring good linear advancement property at traveling while ensuring comfortable workability of a usual attachment work and easily escaping from a muddy place or the like.
The hydraulic control device for the construction machine has a first connection embodiment where left and right traveling motors 20, 24 are divided with respect to two pump lines and are functioned. When a predetermined condition is regulated, it is switched to a second connection embodiment where both of the left and right traveling motors 20, 24 are functioned in a line of a single front pump 12 by a traveling linear advancement valve 50. When any one of traveling system and the other actuator is simultaneously operated (pressure switches 80, 82 are turned on) and it is determined that a line pressure Po of the line 60 of the traveling system is a predetermined value or lower, it is regarded that idle running is generated in any traveling system, an electromagnetic selector valve 58 is switched to side Y and the traveling linear advancement valve 50 is returned to the first connection embodiment (side A).
Satoshi Takaya
Keisuke Matsuyama
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