A height adjustment device for an imaging apparatus includes a driving shaft, first and second moving bodies and a driving device. The driving shaft is configured to rotate in a main body of an imaging apparatus. The driving shaft has first and second spiral grooves defined on a peripheral surface thereof such that the first spiral groove has a first pitch along the driving shaft and a second spiral groove has a second pitch different from the first pitch along the driving shaft. The first moving body has a screw thread engaged with the first spiral groove of the driving shaft. The second moving body has a screw thread engaged with the second spiral groove of the driving shaft The driving device rotates the driving shaft.