PURPOSE: To improve the (working environment and enhance the utilization efficiency of lubricating oil.

CONSTITUTION: There are provided a first connection 12 being connected to a means where lubricating oil with pressure is fed, and a body part 13 being formed in this first connection 12 as one body and with a nut part 17. Also there are provided a valve element 14 being housed in an inner part of the body part 13 and possible to check any lubricating oil from the first connection 12, and an energizing means 15 for energizing the valve element 14 so as to open the valve element 14 by dint of more than the specified pressure. In addition, a second connection 16 being formed solidly with the body part 13 and conducting the lubricating oil run past the valve element and a nut part 17 performing connection between the second connection 16 and an external pipeline 18 both are installed there.