A super-precision evaluation method of the coefficient of thermal expansion (CTE) of ultra-low expansion glasses was developed using the line-focus-beam ultrasonic material characterization (LFB-UMC) system. Evaluation was demonstrated for TiO2-SiO2 glass. The sensitivity and resolution in the velocity measurement of leaky surface acoustic waves (LSAWs) in CTE were estimated to be 4.40 (ppb/K)/(m/s) and ±0.77 ppb/K for ±2σ (σ: standard deviation) at 225 MHz. LSAW velocity differences caused by different TiO2 concentrations and distributions or striae in the specimens were successfully detected and evaluated, providing two-dimensional information under the nondestructive and noncontact measurement condition. This ultrasonic method is much more accurate than conventional methods, for evaluating CTE on the surface of ultra-low-expansion glass materials needed for extreme ultra-violet lithography (EUVL) systems.