1. A power converter comprising:a housing comprising:
a first space in which a circuit substrate is disposed; and
a second space in which a passage for a cooling fluid is disposed;
at least one circuit element disposed on the circuit substrate in the first space and protruding into the second space; and
a cover covering at least a portion of the at least one circuit element and comprising a first portion and a second portion, the first portion protruding from near the circuit substrate into the second space and defining a first region that comprises a first area, the second portion protruding from the first portion in a direction in which the circuit element protrudes and defining a second region that comprises a second area, the first area being larger than the second area as viewed from the direction in which the circuit element protrudes,
wherein the direction that the circuit element protrudes is perpendicular to a wall partitioning the first space from the second space.