A work machine operation assistance device, which is installed in a work machine having a working device driven by an actuator (16, 17, 18) and an operating device (30, 31, 32) to operate the actuator (16, 17, 18), to assist an operator in operating the operating device (30, 31, 32), comprising: a manipulation gain storage section that stores manipulation gain for determining a drive speed of the actuator (16, 17, 18) in relation to a manipulated variable of the operating device (30, 31, 32); and a manipulated variable detection section that detects a manipulated variable of the operating device (30, 31, 32), characterized in that the work machine operation assistance device further comprises: a time integration section that adds up time that the operating device (30, 31, 32) is operated; a manipulated-variable frequency arithmetic section that computes a manipulated-variable frequency of the operating device (30, 31, 32) on the basis of the manipulated variable detected by the manipulated variable detection section and a time integration value obtained at the time integration section; a manipulated-variable frequency criterion setting section that presets a criterion value for the manipulated-variable frequency; a manipulation gain update arithmetic section that performs a computation to update the manipulation gain by use of the manipulated-variable frequency obtained at the manipulated-variable frequency arithmetic section and the criterion value set at the manipulated-variable frequency criterion setting section; a manipulation gain display section that displays a result of the manipulation gain computed by the manipulation gain update arithmetic section; and a manipulation gain update selection section to select whether or not the manipulation gain stored in the manipulation gain storage section is updated to the manipulation gain displayed on the manipulation gain display section. a manipulation gain storage section that stores manipulation gain for determining a drive speed of the actuator (16, 17, 18) in relation to a manipulated variable of the operating device (30, 31, 32); and a manipulated variable detection section that detects a manipulated variable of the operating device (30, 31, 32), characterized in that the work machine operation assistance device further comprises: a time integration section that adds up time that the operating device (30, 31, 32) is operated; a manipulated-variable frequency arithmetic section that computes a manipulated-variable frequency of the operating device (30, 31, 32) on the basis of the manipulated variable detected by the manipulated variable detection section and a time integration value obtained at the time integration section; a manipulated-variable frequency criterion setting section that presets a criterion value for the manipulated-variable frequency; a manipulation gain update arithmetic section that performs a computation to update the manipulation gain by use of the manipulated-variable frequency obtained at the manipulated-variable frequency arithmetic section and the criterion value set at the manipulated-variable frequency criterion setting section; a manipulation gain display section that displays a result of the manipulation gain computed by the manipulation gain update arithmetic section; and a manipulation gain update selection section to select whether or not the manipulation gain stored in the manipulation gain storage section is updated to the manipulation gain displayed on the manipulation gain display section. a time integration section that adds up time that the operating device (30, 31, 32) is operated; a manipulated-variable frequency arithmetic section that computes a manipulated-variable frequency of the operating device (30, 31, 32) on the basis of the manipulated variable detected by the manipulated variable detection section and a time integration value obtained at the time integration section; a manipulated-variable frequency criterion setting section that presets a criterion value for the manipulated-variable frequency; a manipulation gain update arithmetic section that performs a computation to update the manipulation gain by use of the manipulated-variable frequency obtained at the manipulated-variable frequency arithmetic section and the criterion value set at the manipulated-variable frequency criterion setting section; a manipulation gain display section that displays a result of the manipulation gain computed by the manipulation gain update arithmetic section; and a manipulation gain update selection section to select whether or not the manipulation gain stored in the manipulation gain storage section is updated to the manipulation gain displayed on the manipulation gain display section.