An exhaust gas treatment equipment for a large displacement marine diesel engine using lower-grade fuel than fuel oil, comprising: - an electrical precipitation means including a discharge electrode for charging particulate matter contained in exhaust gas of a large displacement marine diesel engine using lower-grade fuel than fuel oil, - and a tubular collecting part with a predetermined length for constituting a precipitation electrode for collecting the charged particulate matter, ∘ the tubular collecting part having an inner circumferential face and an axis, ∘ whereby an exhaust gas delivery pipe for particulate matter of low concentration is provided in the vicinity of the axial center on a downstream side of the tubular collecting part, ∘ whereby an exhaust gas delivery portion (1-lb) for particulate matter of high concentration is provided in the vicinity of the inner circumferential face on the downstream side of the tubular collecting part, - whereby the discharge electrode being composed of a main electrode arranged in the tube axis direction of the tubular collecting part and a plurality of electrode needles, the electrode needles being disposed at intervals on the main electrode and projecting radially, and - a precipitation means (2, 12) for separating and collecting the particulate matter detached from the tubular collecting part, - whereby said precipitation means (2, 12) for collecting the particulate matter is provided to be continuous to the exhaust gas delivery portion for the particulate matter of high concentration, characterized in that - a recirculation pipe (2-2, 12-2) for causing purified gas after passing through the precipitation means (2, 12) to recirculate is provided from the precipitation means (2, 12) to an exhaust gas introduction pipe (1-la) that is provided at an upstream end of the tubular collecting part, - and a flow rate control damper is provided in the low-PM-concentration exhaust gas delivery pipe, - and a kinetic energy imparting means to exhaust gas recirculating in the recirculation pipe (2-2, 12-2) is arranged - so that an exhaust gas inflow velocity into the precipitation means (2, 12) is controlled by controlling an opening degree of the damper arranged in the exhaust gas delivery pipe for particulate matter of low concentration and/or a the kinetic energy imparting means to the exhaust gas. - an electrical precipitation means including a discharge electrode for charging particulate matter contained in exhaust gas of a large displacement marine diesel engine using lower-grade fuel than fuel oil, - and a tubular collecting part with a predetermined length for constituting a precipitation electrode for collecting the charged particulate matter, ∘ the tubular collecting part having an inner circumferential face and an axis, ∘ whereby an exhaust gas delivery pipe for particulate matter of low concentration is provided in the vicinity of the axial center on a downstream side of the tubular collecting part, ∘ whereby an exhaust gas delivery portion (1-lb) for particulate matter of high concentration is provided in the vicinity of the inner circumferential face on the downstream side of the tubular collecting part, ∘ the tubular collecting part having an inner circumferential face and an axis, ∘ whereby an exhaust gas delivery pipe for particulate matter of low concentration is provided in the vicinity of the axial center on a downstream side of the tubular collecting part, ∘ whereby an exhaust gas delivery portion (1-lb) for particulate matter of high concentration is provided in the vicinity of the inner circumferential face on the downstream side of the tubular collecting part, - whereby the discharge electrode being composed of a main electrode arranged in the tube axis direction of the tubular collecting part and a plurality of electrode needles, the electrode needles being disposed at intervals on the main electrode and projecting radially, and - a precipitation means (2, 12) for separating and collecting the particulate matter detached from the tubular collecting part, - whereby said precipitation means (2, 12) for collecting the particulate matter is provided to be continuous to the exhaust gas delivery portion for the particulate matter of high concentration, characterized in that - a recirculation pipe (2-2, 12-2) for causing purified gas after passing through the precipitation means (2, 12) to recirculate is provided from the precipitation means (2, 12) to an exhaust gas introduction pipe (1-la) that is provided at an upstream end of the tubular collecting part, - and a flow rate control damper is provided in the low-PM-concentration exhaust gas delivery pipe, - and a kinetic energy imparting means to exhaust gas recirculating in the recirculation pipe (2-2, 12-2) is arranged - so that an exhaust gas inflow velocity into the precipitation means (2, 12) is controlled by controlling an opening degree of the damper arranged in the exhaust gas delivery pipe for particulate matter of low concentration and/or a the kinetic energy imparting means to the exhaust gas.