Abstract: According to an aspect of the present invention, movement of the AF area by the AF area operation device can be made ineffective by the switching device, and thereby, even if the operator moves the manual operation member by mistake, the AF area does not move, and the AF area can be securely kept at a predetermined position. According to another aspect of the present invention, it is possible to instantaneously return the AF area which has been moved to a position different from the initial position, to the initial position by the reset device.

Abstract: A particulate trap for use in a diesel engine can efficiently trap particulates contained in exhaust gas with low pressure drop and can burn collected particulates for regeneration with less power consumption. A filter element having a built-in electric heater is mounted in a case provided in the exhaust line of a diesel engine. The filter has two mutually opposed surfaces between which is mounted the electric heater. With this arrangement, it is possible to increase the filtration area and also the heating efficiency.