An absolute position measuring device includes a main body, a spindle (300), a rotary encoder (500), a linear encoder (600), and an arithmetic processor (720). The rotary encoder (500) has a rotor plate encoder (520) that rotates integrally with the spindle (300). A rotary cylinder (530) rotates integrally with the spindle (300) and has an external thread (531). A nut member (610) is engaged with the external thread (531) of the rotary cylinder (530) in a rotation stop state. The linear encoder (600) has a slider (620) that slides together with the nut member (610), and a detection scale (630) that detects the slider position. The rotary encoder (500) absolutely detects the rotary angle of the rotor plate (520) within one revolution, and the linear encoder (600) absolutely detects the position of the slider (620).