WORK MACHINE

A work machine includes: a work device; an operation device operating the work device; a first controller controlling operation of the work device on the basis of operation of the operation device; and a second controller determining that an auto idle condition is satisfied and performing auto idle control that decreases an engine revolution speed to an idle revolution speed in case the operation device is not operated for a predetermined time. The first controller diagnoses presence or absence of a failure in the first controller when supply of power to the first controller is started. The second controller performs power interruption control that interrupts the supply of the power to the first controller in case the auto idle condition is satisfied, and performs power supply control that starts the supply of the power to the first controller afterward.