A valve device increases or decreases a flow rate of EGR gas. The valve device includes a housing, a bypass valve body, and an EGR valve body. The housing includes a first upstream passage into which the EGR gas cooled by an EGR cooler flows, a second upstream passage into which the EGR gas that bypasses the EGR cooler flows, and a downstream passage connected to the first upstream passage and the second upstream passage, and provided downstream with respect to the first upstream passage and the second upstream passage. The bypass valve body opens and closes the second upstream passage. The EGR valve body is provided in the downstream passage and rotates around an EGR valve axis to open and close the downstream passage.