PURPOSE: To make static characteristic and dynamic characteristic most suitable by providing, a counter balance valve with a spool which is positioned by driving force and spring force applied on end surfaces and on both ends of which an oil chamber is formed and connecting a valve outlet side to one side oil chamber through a throttle adjusting device interposing oil passage, in the counter balance circuit of a construction machine and the like.

CONSTITUTION: A spool 18 is provided in a counter balance valve 17 provided on the return side of a hydraulic motor 14. The spool 18 is positioned by spool driving force applied on an end surface (SA) and force of a spring applied on an end surface (SB). Oil chambers 17a, 17b are formed on both sides of the spool 18. The oil chamber 17b in which the spring 19 is arranged is connected to the outlet side of the counter balance valve 17 through an oil passage (L3), and a variable throttle 25 is provided to be adjusted by a throttle adjuster 26. The oil chamber 17a is connected to the supplying side oil passage (L1) of the hydraulic motor 14.