Provided is a mower unit mountable to a traveling vehicle body. The mower unit includes a mower deck, a plurality of blades supported to the mower deck to be rotatable about vertical rotational axes, and a rear vacuum plate disposed rearwardly of rotational locus circles of the plurality of blades and attached to a lower face of the mower deck. The rear vacuum plate includes a plurality of arcuate portions formed arcuate to extend along the respective rotational locus circles of the blades and a convexly curved portion curved to extend into a triangular gap portion formed between two adjacent rotational locus circles, the convex curved portion bridging opposed ends of two adjacent arcuate portions. The convexly curved portion and the arcuate portions are connected to maintain a continuous curve.