A PCV valve may include a housing and a valve member movable in an axial direction within the housing. A plurality of guide portions may be formed on the valve member, so that the plurality of guide portions slidably contact the monitoring portion of the housing as the valve member moves in the axial direction. When a first part of a tapered portion of the valve member opposes to the monitoring portion, a first contact part of each of the guide portions may contact the monitoring portion. When a second part of the tapered portion having a smaller diameter than the first part opposes to the monitoring portion, a second contact part of each of the guide portions may contact the monitoring portion. The second contact part may be smaller than the first part with respect to a width in a circumferential direction or may have a circumferential contact length smaller than that of the first part.