A humidifier for a respiratory apparatus includes a first cover, a second cover engaged with the first cover and a partition plate. The first cover defines an air inlet. The second cover defines a chamber configured to contain at least some amount of water. A heater is configured to heat the water to generate humidified air in the chamber. The partition plate is partly sandwiched between the first cover and the second cover. The partition plate defines an air outlet. Air input via the air inlet is humidified by being mixed with the humidified air and thereafter ejected through the air outlet. The air entering via the air inlet is divided by the partition plate into a plurality of flows having different flow velocities, thereby forming a plurality of flow paths.