To provide a workpiece pressing-in device capable of certainly pressing-in an annular workpiece to a shaft and certainly detecting circumstances of the pressing-in load at that time.

The workpiece pressing-in device includes a pressing-in unit 14 for pressing-in the annular workpiece 5 to a predetermined mounting position e1 in an axial direction of the shaft-like workpiece 3 formed with an annular recess 301 on an outer peripheral surface. The pressing-in unit 14 has: a shaft clamping means 39 for clamping the annular recess 301 by a clamping member driven by a first driving means 35; and a pressing-in means comprising a servo-press 19 in which a second driving means independent from the first driving means 35 applies pressing-in force to the annular workpiece 5 through a pressing-in force transmission member 31. The annular recess 301 of the shaft is clamped by the shaft clamping means 39 without deviation, and the pressing-in means presses-in the annular workpiece 5 to the mounting position e1.