A means capable of supplying exhaust gas sufficiently imitating exhaust gas from actual diesel engines is provided. A PM generating apparatus has a constitution in which combustion air supplied to the space between a chassis and an outer casing via an air inlet is introduced into the space between the outer casing and an inner casing via through-holes of the outer casing, and a fuel injected by an fuel-injection means into the space between the chassis and the outer casing is introduced into the space between the outer casing and the inner casing via the through-holes of the outer casing, wherein the fuel is combusted to generate PM.