Abstract: This study investigates the impact of linear motion on the perception of melodic intervals using a six-degree-of-freedom motion simulator. Using the magnitude estimation method across the platform’s three translational degrees of freedom—the mutually perpendicular X-, Y-, and Z-axes of a spatial rectangular coordinate system—participants were asked to compare their auditory perception of melodic intervals under both motion and static conditions. The aim was to determine whether linear motion of the platform affects the auditory perception of melodic interval direction and the pitch distance (in cents) between two notes. Results revealed that linear motion along all three translational axes influenced the perceived size of melodic intervals. Moreover, interactions among motion direction, melodic interval direction, and melodic interval size modulated changes in perceived interval distance (in cents).