The present invention provides a phenolic resin foam board, which exhibits sufficient compressive strength and heat conductivity for practical use even when the thickness of the phenolic resin foam board is increased, and which has superior dimensional stability compared with conventional products. The present invention is a phenolic resin foam board which has a board thickness of 40 to 300 mm inclusive. The phenolic resin foam board satisfies the formula 0<=(dave-dmin)/dave<=0.12, where dn represents the density of a nth specimen among n (n>=5) pieces of specimens that are produced by slicing the phenolic resin foam board at almost equal intervals of 8 to 10 mm inclusive in the thickness direction from one main surface of the phenolic resin foam board along the main surface, dave represents the average density of the n pieces of specimens, and dmin represents the lowest density among the densities of the n pieces of specimens. When values for Di=(di+d(i+1))/2 are calculated [where i represents an integer of 1 to (n-1)], the Di values are plotted in the order of the numerical values of i (where the horizontal axis indicates the i values and the vertical axis indicates Di values), and points corresponding to the Di values are connected to produce a density distribution curve, there is no straight line that intersects the density distribution curve at four points and is parallel to the horizontal axis.