A loader work machine includes: a first lift link (81) and a second lift links (82) disposed forwardly of the first lift link (81) for vertically pivotally supporting a base portion of an arm (77) at a rear upper portion of a machine body frame (1); an arm cylinder (79) provided between the base portion of the arm (77) and a rear lower portion of the machine body frame for lifting up/down the arm (77); a first link support shaft (85) for pivotally supporting a lower base portion of the first lift link (81) to the machine body frame (1); a second link support shaft (86) for pivotally connecting a base portion of the second lift link (82) to the machine body frame (1), at a position forwardly of the first link support shaft; a first arm support shaft (88) for pivotally supporting a base portion of the arm (77) to an upper free end of the first lift link (81); a second arm support shaft (89) for pivotally connecting a base portion of the arm (77) to a free end of the second lift link (82), at a position forwardly of the first arm support shaft (88); a lower cylinder support shaft (91) for pivotally connecting a lower end of the arm cylinder (79) to the machine body frame (1); and an upper cylinder support shaft (92) for pivotally connecting an upper leading end portion of the arm cylinder (79) to the base portion of the arm (77). A leading end of the arm (77) is lifting up/down forwardly of the machine body frame (1). Positional relationship among the first link support shaft (85), the second link support shaft (86), the first arm support shaft (88) and the second arm support shaft (89) is set such that an upper portion of the first lift link (81) comes into substantial agreement with a rear end of the machine body (1), when the upper free end of the first lift link (81) is pivoted maximally rearward in the course of transition of the arm (77) from a lowermost state realized lifting down the arm (77) to an uppermost state realized by lifting up the arm (77).