An engine control device adapted to control a power output of an engine of a working vehicle provided with a work apparatus, comprising: one or more detectors adapted to detect one or more of variable values which indicate a state or states of one or more work loads which consume a power output from an engine and include a load imparted by said work apparatus; and a controller adapted to control a power output capacity of said engine based upon said detected one or more variable values which have been detected by said one or more detectors, wherein said one or more detectors include at least one of a work apparatus operation detector adapted to detect an operation of said work apparatus and a work apparatus position detector adapted to detect a position or an attitude of said work apparatus; wherein the engine control device is provided in a working vehicle comprising a work machine which is driven by a hydraulic pressure generated by consuming at least a part of the power output of the engine and performs one or a plurality of operations; and a travel device which is driven by at least a part of the power output of the engine and causes the working vehicle to travel, the travel device comprising a transmission having a plurality of selectable speed stages for forward travel and backward travel, said engine control device being characterized in that: the controller is capable of selecting, as a selected control mode, either a low output mode for limiting the output torque of the engine to a range not exceeding a predetermined upper limit output torque curve, or a high output mode for permitting the output torque of the engine to exceed the upper limit output torque curve, and, when the selected control mode is the low output mode, the controller switches the selected control mode from the low output mode to the high output mode if said hydraulic pressure rises to exceed a predetermined first pressure value after having been staying at or below the first pressure value for at least a predetermined first time period. one or more detectors adapted to detect one or more of variable values which indicate a state or states of one or more work loads which consume a power output from an engine and include a load imparted by said work apparatus; and a controller adapted to control a power output capacity of said engine based upon said detected one or more variable values which have been detected by said one or more detectors, wherein said one or more detectors include at least one of a work apparatus operation detector adapted to detect an operation of said work apparatus and a work apparatus position detector adapted to detect a position or an attitude of said work apparatus; a work machine which is driven by a hydraulic pressure generated by consuming at least a part of the power output of the engine and performs one or a plurality of operations; and a travel device which is driven by at least a part of the power output of the engine and causes the working vehicle to travel, the travel device comprising a transmission having a plurality of selectable speed stages for forward travel and backward travel, the controller is capable of selecting, as a selected control mode, either a low output mode for limiting the output torque of the engine to a range not exceeding a predetermined upper limit output torque curve, or a high output mode for permitting the output torque of the engine to exceed the upper limit output torque curve, and, when the selected control mode is the low output mode, the controller switches the selected control mode from the low output mode to the high output mode if said hydraulic pressure rises to exceed a predetermined first pressure value after having been staying at or below the first pressure value for at least a predetermined first time period.