A work-machine erroneous forward/backward travelling operation notifying apparatus, comprising: a transmission including a clutch (121, 122, 123, 124) that includes: a forward travelling clutch (121, 122, 123) that is engaged by a hydraulic oil discharged from a hydraulic pump when a travelling body travels forward; and a backward travelling clutch that is engaged by the hydraulic oil discharged from the hydraulic pump when a travelling body travels backward; a forward travelling hydraulic oil flow path that allows the hydraulic oil to flow through when the forward travelling clutch (121, 122, 123) is engaged; a backward travelling hydraulic oil flow path that allows the hydraulic oil to flow through when the backward travelling clutch is engaged; a flow path switching mechanism (133, 134) that switches a flow path for the hydraulic oil discharged from the hydraulic pump to a forward travelling hydraulic oil flow path side or a backward travelling hydraulic oil flow path side; a forward travelling pressure sensor that detects pressure in the forward travelling hydraulic oil flow path; a backward travelling pressure sensor that detects pressure in the backward travelling hydraulic oil flow path; an operation input section configured to be operated for inputting an operation that causes the travelling body to travel forward or travel backward; a state determination section that determines whether or not a state of the clutch (121, 122, 123, 124) coincides with a travel direction inputted to the operation input section, based on at least one of detected pressure of the forward travelling pressure sensor and detected pressure of the backward travelling pressure sensor and the travel direction inputted to the operation input section; and a notification section that notifies, before the travelling body starts to travel, that an erroneous operation is to occur on the travelling body, when it is determined that the state of the clutch (121, 122, 123, 124) does not coincide with the travel direction inputted to the operation input section by the state determination section. a transmission including a clutch (121, 122, 123, 124) that includes: a forward travelling clutch (121, 122, 123) that is engaged by a hydraulic oil discharged from a hydraulic pump when a travelling body travels forward; and a backward travelling clutch that is engaged by the hydraulic oil discharged from the hydraulic pump when a travelling body travels backward; a forward travelling clutch (121, 122, 123) that is engaged by a hydraulic oil discharged from a hydraulic pump when a travelling body travels forward; and a backward travelling clutch that is engaged by the hydraulic oil discharged from the hydraulic pump when a travelling body travels backward; a forward travelling hydraulic oil flow path that allows the hydraulic oil to flow through when the forward travelling clutch (121, 122, 123) is engaged; a backward travelling hydraulic oil flow path that allows the hydraulic oil to flow through when the backward travelling clutch is engaged; a flow path switching mechanism (133, 134) that switches a flow path for the hydraulic oil discharged from the hydraulic pump to a forward travelling hydraulic oil flow path side or a backward travelling hydraulic oil flow path side; a forward travelling pressure sensor that detects pressure in the forward travelling hydraulic oil flow path; a backward travelling pressure sensor that detects pressure in the backward travelling hydraulic oil flow path; an operation input section configured to be operated for inputting an operation that causes the travelling body to travel forward or travel backward; a state determination section that determines whether or not a state of the clutch (121, 122, 123, 124) coincides with a travel direction inputted to the operation input section, based on at least one of detected pressure of the forward travelling pressure sensor and detected pressure of the backward travelling pressure sensor and the travel direction inputted to the operation input section; and a notification section that notifies, before the travelling body starts to travel, that an erroneous operation is to occur on the travelling body, when it is determined that the state of the clutch (121, 122, 123, 124) does not coincide with the travel direction inputted to the operation input section by the state determination section.