A switching valve comprises a housing, a gas inflow chamber, a first passage adjacent to the inflow chamber through a first partition wall and communicating with the EGR cooler, a first communication hole providing communication between the inflow chamber and the first passage, a gas outflow passage, a second passage communicating with the outflow passage and adjacent to the inflow chamber through the second partition wall and communicating with the EGR cooler, a second communication hole formed in the second partition wall and providing communication between the inflow chamber and the second passage, and a third partition wall dividing the first passage from the second passage. The first to third partition walls are continuous at a joined portion in a Y-shaped cross section. A valve element is placed to be swingable about a point near the joined portion between the first and second partition walls. The first and second partition walls are slanted with respect to a mold-removing direction to form the inflow chamber and the third partition wall is parallel to a mold-removing direction to form the first and second passages.