PROBLEM TO BE SOLVED: To configure a paddy work machine so that an ultrasonic sensor can be effectively used to appropriately detect a depth of a field (depth from a field scene to a tiller). SOLUTION: A working device that is supported by the machine body 11 and supplies seedlings or seeds to a field scene G2, and an ultrasonic sensor 29 that is attached to the machine body 11 and detects a height H1 from the field scene G2 to the machine body 11 are provided. Be prepared. Based on the detection value of the ultrasonic sensor 29 and the positional relationship between the front and rear wheels of the machine body 11 and the ultrasonic sensor 29, the depth A2 from the field scene G2 to the cultivator G1 where the front and rear wheels contact the ground is set. A depth detector 39 for detecting is provided. [Selection diagram] Fig. 3【課題】水田作業機において、超音波センサーを有効に利用して、圃場の深さ（圃場面から耕盤までの深さ）を適切に検出することができるように構成する。【解決手段】機体１１に支持されて圃場面Ｇ２に苗又は種籾を供給する作業装置と、機体１１に取り付けられて圃場面Ｇ２から機体１１までの高さＨ１を検出する超音波センサー２９とが備えられる。超音波センサー２９の検出値、並びに、機体１１における前輪及び後輪と超音波センサー２９との位置関係に基いて、圃場面Ｇ２から前輪及び後輪が接地する耕盤Ｇ１までの深さＡ２を検出する深さ検出部３９が備えられる。【選択図】図３
