A work vehicle transmission comprising: a plurality of transmission shafts that extend parallel with each other in a front-rear direction of a vehicle body, the plurality of transmission shafts including a speed change shaft and a deceleration shaft; a multi-stage transmission apparatus including: a first transmission mechanism configured to change input motive power to any one of a plurality of speeds, the first transmission mechanism having a plurality of speed change gear sets, and a plurality of speed change multi-disc clutches that are arranged adjacent in the front-rear direction on the speed change shaft and engage and disengage power transmission to the plurality of speed change gear sets; and a second transmission mechanism configured to change motive power changed by the first transmission mechanism to any one of a plurality of speeds, the number of speeds of the second transmission mechanism being smaller than the number of speeds of the first transmission mechanism, and the second transmission mechanism having a plurality of deceleration gear sets (64,65), and a plurality of deceleration multi-disc clutches (66,67) that are arranged on the deceleration shaft and engage and disengage power transmission to the plurality of deceleration gear sets (64,65), wherein the plurality of transmission shafts further includes an intermediate shaft arranged between the speed change shaft and deceleration shaft, the speed change multi-disc clutches and the deceleration multi-disc clutches (66,67) not being arranged coaxially with the intermediate shaft, characterized by in a front view of the vehicle body, the speed change shaft, the intermediate shaft and an axis of the deceleration shaft are arranged so as to form an isosceles triangle having the intermediate shaft as an upper vertex, and in a front view of the vehicle body, assuming that there are formed a pair of triangular virtual spaces (90, 91) that each virtual space has, as one side, a virtual line interconnecting an axis of the speed change shaft and an axis of the deceleration shaft and that are above and below the virtual line, and assuming that each virtual space has a larger height than a height of the isosceles triangle, the intermediate shaft is inserted into one of the virtual spaces on an upper side. a plurality of transmission shafts that extend parallel with each other in a front-rear direction of a vehicle body, the plurality of transmission shafts including a speed change shaft and a deceleration shaft; a multi-stage transmission apparatus including: a first transmission mechanism configured to change input motive power to any one of a plurality of speeds, the first transmission mechanism having a plurality of speed change gear sets, and a plurality of speed change multi-disc clutches that are arranged adjacent in the front-rear direction on the speed change shaft and engage and disengage power transmission to the plurality of speed change gear sets; and a second transmission mechanism configured to change motive power changed by the first transmission mechanism to any one of a plurality of speeds, the number of speeds of the second transmission mechanism being smaller than the number of speeds of the first transmission mechanism, and the second transmission mechanism having a plurality of deceleration gear sets (64,65), and a plurality of deceleration multi-disc clutches (66,67) that are arranged on the deceleration shaft and engage and disengage power transmission to the plurality of deceleration gear sets (64,65), a first transmission mechanism configured to change input motive power to any one of a plurality of speeds, the first transmission mechanism having a plurality of speed change gear sets, and a plurality of speed change multi-disc clutches that are arranged adjacent in the front-rear direction on the speed change shaft and engage and disengage power transmission to the plurality of speed change gear sets; and a second transmission mechanism configured to change motive power changed by the first transmission mechanism to any one of a plurality of speeds, the number of speeds of the second transmission mechanism being smaller than the number of speeds of the first transmission mechanism, and the second transmission mechanism having a plurality of deceleration gear sets (64,65), and a plurality of deceleration multi-disc clutches (66,67) that are arranged on the deceleration shaft and engage and disengage power transmission to the plurality of deceleration gear sets (64,65), wherein the plurality of transmission shafts further includes an intermediate shaft arranged between the speed change shaft and deceleration shaft, the speed change multi-disc clutches and the deceleration multi-disc clutches (66,67) not being arranged coaxially with the intermediate shaft, characterized by in a front view of the vehicle body, the speed change shaft, the intermediate shaft and an axis of the deceleration shaft are arranged so as to form an isosceles triangle having the intermediate shaft as an upper vertex, and in a front view of the vehicle body, assuming that there are formed a pair of triangular virtual spaces (90, 91) that each virtual space has, as one side, a virtual line interconnecting an axis of the speed change shaft and an axis of the deceleration shaft and that are above and below the virtual line, and assuming that each virtual space has a larger height than a height of the isosceles triangle, the intermediate shaft is inserted into one of the virtual spaces on an upper side.