To provide a flame-retardant polyurethane foam that does not emit a smell such as a cresol smell etc., for a long period of time and is suitably useful as a vehicle seat cushion.

Provided is a flame-retardant polyurethane foam prepared by using a raw material comprising at least a polyetherol, ethylene glycol and/or diethylene glycol, an isocyanate, a blowing agent and a flame retardant, characterized in that the flame retardant is a phosphate having t-butylphenyl.