Patent ID: 7234296

Claim:
An exhaust gas purifier that filters exhaust gas from an internal combustion engine to collect particulates in the exhaust gas, the exhaust gas purifier comprising: an outer casing and an inner casing, which is located inside the outer casing and accommodates, wherein the inner casing is selectively attached to and detached from the outer casing; and retaining means for retaining the inner casing to the outer casing, wherein the retaining means is located apart from a downstream end surface of the filter by a predetermined distance, and has at least one of exhaust gas emitting hole, wherein the open area rate of the gas emitting hole to the retaining means is set to 20 to 60%, and wherein the retaining means retains the inner casing in the outer casing when the retaining means is integrally connected to the outer casing from downstream of the filter, and the inner casing is detachable from the outer casing when the retaining means is detached from the outer casing.