The present invention employs the following technical means to solve the above-mentioned problems. That is, first, the first invention includes a pair of inclined leaf raising devices 3 and 3 ′ each having an inclined front end having a forward end at a front lower portion and an end portion having a rear upper end at a front portion of a chassis 2 having a traveling device 1. The leaf stem raising devices 3 and 3 'are provided with the raising passages 5 facing the raising lugs 4 on both sides facing each other at a high position in a C-shape when viewed from the front, and are provided below the leaf stem raising devices 3 and 3'. A leaf cutting device 6 is provided in close proximity to the raising passage 5, and the rear end of the leaf cutting device 6 faces a starting end of a leaf transporting device for transporting the cutting leaf from the middle portion of the chassis 2 to the rear. This is a leaf stem treatment device provided with an onion harvester.