A camshaft (2) comprising a decompression device (1) to reduce pressure in a cylinder when an engine starts, the camshaft (2) having first and second lobes (14, 15) for actuating cylinder valves (62). The decompression device (1) has a shaft (10) located axially within the camshaft (2), and rotatable relative to the camshaft (2) to extend or retract a first and a second lifter (12, 13) radially. The first and second lifters (12, 13) are respectively provided inwardly of lobe faces of the first and second lobes (14, 15) on the camshaft (2) in a radial direction of the camshaft (2) such that the first lifter and the second lifter (12, 13) can extend outwardly or retract inwardly in the radial direction from the lobe faces. The shaft (10) has first and second eccentric portions (10A, 10B) located in transverse slots (12B, 13B) in the first and second lifters (12, 13) to extend or retract the first and second lifters (12, 13) respectively. The second lifter (13) has a longitudinal cut-out (13C) extending to the transverse slot (13B) of the second lifter (13) to allow the second eccentric portion (10B) to enter the transverse slot (13B).