Substrate processing apparatuses and methods of manufacturing a semiconductor device using the same may be provided. A substrate processing apparatus includes a heater in a support plate and comprising a first unit configured to heat a first portion of a substrate and a second unit configured to heat a second portion of a substrate, and processing circuitry configured to heat the heater in a transient section such that the first unit heats the first portion of the substrate to a first heating temperature, and the second unit heats the second portion of the substrate to a second heating temperature different from the first heating temperature, the transient section being a section before a temperature of the substrate reaches a steady state, a steady section being a section after the temperature of the substrate reaches the steady state.