A dense composite material according to the present invention contains, in descending order of content, silicon carbide, titanium silicon carbide, and titanium carbide as three major constituents. The dense composite material contains 51% to 68% by mass of silicon carbide and no titanium silicide and has an open porosity of 1% or less. This dense composite material has properties such as an average linear thermal expansion coefficient of 5.4 to 6.0 ppm/K at 40° C. to 570° C., a thermal conductivity of 100 W/m·K or more, and a four-point bending strength of 300 MPa or more.