PROBLEM TO BE SOLVED: To provide a riding working machine capable of reliably protecting an electric motor, which is used to drive a working device, while preventing degradation of working efficiency without an increase in a cost.SOLUTION: A riding working machine includes: a speed designation operating device which a driver maneuvers so as to designate a target travel speed of a machine； a travel control unit 54 that controls traveling electric motors 21 and 22 on the basis of the target travel speed； a working device with which work is performed on an object of work, which lies around a vehicle body, along with traveling of the machine； working electric motors 31, 32, and 33 with which the working device is driven； a work control unit 58 that controls the working electric motors 31, 32, and 33； temperature sensors 91a, 91b, and 91c that detect the temperatures of the traveling electric motors 31, 32, and 33 respectively； and an exceptional speed control unit 55 that implements exceptional speed control under which the traveling electric motors 21 and 22 are controlled at an exceptional speed lower than the target travel speed in a case where the temperatures detected by the temperature sensors 91a, 91b, and 91c respectively are higher than a threshold.【課題】コストを増大させることなく、作業効率の低下を防止しつつ、作業デバイスを駆動するための電動モータを確実に保護することが可能な乗用作業機が要望されている。【解決手段】機体の目標走行速度を設定するために運転者によって操作される速度設定操作デバイスと目標走行速度に基づいて走行用電動機２１，２２を制御する走行制御部５４と、機体の走行に伴って車体周囲の作業対象物に対する作業を行う作業デバイスと、作業デバイスを駆動するための作業用電動機３１，３２，３３と、作業用電動機３１，３２，３３を制御する作業制御部５８と、走行用電動機３１, ３２，３３の温度を検出する温度センサ９１a，９１ｂ，９１ｃと、温度センサ９１a，９１ｂ，９１ｃによって検出された温度がしきい値より高い場合に目標走行速度より低い例外速度で走行用電動機２１，２２を制御する例外速度制御を実行する例外速度制御部５５とを備えた。【選択図】図３
