The present invention is a phenolic resin foam including a hydrocarbon having a carbon number of 6 or less and a density of the phenolic resin foam is 10 kg/m3 or more and 150 kg/m3 or less, in which, in the phenolic resin foam, the hydrocarbon having a carbon number of 6 or less includes 40 mol % to 90 mol % of cyclopentane and 60 mol % to 10 mol % of one or two or more types selected from hydrocarbons having a boiling point of −50° C. to 5° C.; and the average boiling point X of the hydrocarbon having a carbon number of 6 or less is 5° C. to 44° C. and the content Y of the hydrocarbon having a carbon number of 6 or less in the phenolic resin foam is 0.25 mol to 0.9 mol per of 22.4×10−3 m3 space volume in the phenolic resin foam.