<p>A liquid heating apparatus 1 has a flow path 2 surrounded by a quartz glass tube 5 inside a tubular ceramic heater 4 which radiates infrared rays and has a PTC characteristic, and a flow path 3 which is formed between two quartz glass tubes 6, 7 which are disposed outside the tubular ceramics tube 4 in a coaxial manner. The liquid heating apparatus can effectively heat purified water used for manufacturing electronics-related products without contamination of the purified water, and provides a compact size while having a high heat capacity.</p>