To provide an odorant which causes a high odorizing effect even when used in a more minute amount than a conventional nonsulfur compound odorant and can be used for odorizing a hydrogen gas in a fuel cell.

This odorant essentially contains 5-ethyl-3-hydroxy-4-methyl-2(5 H)-franone and/or 3-hydroxy-4,5-dimethyl-2(5H)-franone and is effective even when used in a minute amount for odorizing a hydrogen gas.