A control handle structure of an excavation work vehicle, characterized in that a maneuvering valve (V.sub.1) for boom swiveling, a maneuvering valve (V.sub.8) for boom up-and-down rocking, a maneuvering valve (V.sub.2) for arm rocking and a maneuvering valve (V.sub.5) for bucket pivoting are disposed substantially in parallel;
- that the four maneuvering valves (V.sub.1),(V.sub.8),(V.sub.2),(V.sub.5) are interlockingly connected, in a manner capable of separate individual maneuvering and capable of simultaneous maneuvering in respective pairs, via first, second, third and fourth interlocking systems (R.sub.1), (R.sub.6), (R.sub.2), (R.sub.5) parallel with one another using respective push-pull rods, to two maneuvering levers (14), (15) adapted for free rocking, bi-directional maneuvering in back-and-forth and right-and-left directions of the vehicle;
- that there is provided, intermediary of the interlocking systems (R.sub.1), (R.sub.6), (R.sub.2), (R.sub.5), an interlocking mode change-over mechanism (30) for changing the mode of the interlocking between said two maneuvering levers (14), (15) and said four maneuvering valves (V.sub.1), (V.sub.8), (V.sub.2), (V.sub.5);
- that the interlocking mode change-over mechanism connects the maneuvering valve (V.sub.1) for boom swiveling and maneuvering valve (V.sub.2) for arm rocking interlockingly with said one maneuvering lever (14) and connects the maneuvering valve (V.sub.8) for boom up-and-down rocking and said maneuvering valve (V.sub.5) for bucket pivoting interlockingly with the said other maneuvering lever (15);
- that the interlocking mode change-over mechanism (30) connects the maneuvering valve (V.sub.1) for boom swiveling and maneuvering valve (V.sub.8) for boom up-and-down rocking interlockingly with said one maneuvering lever (14) and connects the maneuvering valve (V.sub.2) for arm rocking and said maneuvering valve (V.sub.5) for bucket pivoting interlockingly with said other maneuvering lever (15);
- that in the interlocking mode change-over mechanism (30) there is rotatably provided an arm-maneuvering intermediary pipe shaft (31) and a boom-maneuvering intermediary pipe shaft (32), these intermediary pipe shafts (31), (32), being disposed with their rotation axes extending in the direction normal to the maneuvering direction of respective juxtaposed push-pull rods (20a), (20b), (28a-d) of the third interlocking system (R.sub.2), and the second interlocking system (R.sub.6);
- that on the arm-maneuvering intermediary pipe-shaft (31) there are protrudingly provided in the same direction a first connection arm (33), for connecting a partial member (20a), made releasable and remountable, out of push-pull rods (20a), (20b), of the third interlocking system (R.sub.2) interlockingly with the one maneuvering lever (14), and a second connection arm (34), for connecting the releasable and remountable push-pull rod (20a) interlockingly with the said other maneuvering lever (15);
- and that on the said boom-maneuvering intermediary pipe shaft (32) there are protrudingly provided in the same direction a first connection arm (36), for connecting a releasable and remountable push-pull rod (28a) of the second interlocking system (R.sub.6)., interlockingly with the one maneuvering lever (14), and a second connection arm (35), for connecting interlockingly with the other maneuvering lever (15).