Fexuprazan is a potassium-competitive acid blocker approved for treating gastric acid-related diseases. Herein, we evaluated the pharmacokinetics (PKs) of single-dose and multiple-dose oral administration of fexuprazan 10 mg tablets in healthy subjects (Part 1) and investigated the bioequivalence between fexuprazan 10 mg and 40 mg tablets (Part 2). Part 1 comprised a single- and multiple-dose, 1-sequence, and 2-period design, and Part 2 comprised a single-dose, 2×2 crossover design. Eight and 23 subjects completed Parts 1 and 2, respectively. In Part 1, multiple doses accumulated twice as much as single doses. In Part 2, the geometric mean ratios [90% confidence intervals] for maximum plasma concentration (Cmax) and area under the concentration–time curve from zero to the time of the last quantifiable concentration (AUClast) of four fexuprazan 10 mg tablets to those of one fexuprazan 40 mg tablet were 1.0290 (0.9352–1.1321) and 1.0290 (0.9476–1.1174), respectively, which met bioequivalence criteria. Overall, favorable PK was observed after single and multiple administrations of one fexuprazan 10 mg tablet, and four fexuprazan 10 mg tablets were pharmacokinetically equivalent to one fexuprazan 40 mg tablet.