A power generation apparatus which generates power using heat comprising: a duct through which a cooling fluid passes; a first thermoelectric module disposed on a first surface of the duct; a second thermoelectric module disposed on a second surface opposite to the first surface of the duct; and a guide member guiding a fluid with a different temperature from the cooling fluid and disposed on a third surface, which is disposed between the first surface and the second surface of the duct to face an inlet of the fluid with the different temperature from the cooling fluid, wherein the guide member includes: one end connected to the first thermoelectric module; the other end connected to the second thermoelectric module; and an extension portion connecting the one end to the other end, the guide member has a shape in which a distance from the guide member to the third surface is increased in a direction toward a center between the one end and the other end, an auxiliary guide member is disposed on at least one of the one end and the other end of the guide member, at least one hole is formed between the auxiliary guide member and the at least one of the one end and the other end of the guide member, and the fluid with the different temperature from the cooling fluid passes through the at least one hole. a duct through which a cooling fluid passes; a first thermoelectric module disposed on a first surface of the duct; a second thermoelectric module disposed on a second surface opposite to the first surface of the duct; and a guide member guiding a fluid with a different temperature from the cooling fluid and disposed on a third surface, which is disposed between the first surface and the second surface of the duct to face an inlet of the fluid with the different temperature from the cooling fluid, wherein the guide member includes: one end connected to the first thermoelectric module; the other end connected to the second thermoelectric module; and an extension portion connecting the one end to the other end, the guide member has a shape in which a distance from the guide member to the third surface is increased in a direction toward a center between the one end and the other end, an auxiliary guide member is disposed on at least one of the one end and the other end of the guide member, at least one hole is formed between the auxiliary guide member and the at least one of the one end and the other end of the guide member, and the fluid with the different temperature from the cooling fluid passes through the at least one hole. one end connected to the first thermoelectric module; the other end connected to the second thermoelectric module; and an extension portion connecting the one end to the other end, the guide member has a shape in which a distance from the guide member to the third surface is increased in a direction toward a center between the one end and the other end, an auxiliary guide member is disposed on at least one of the one end and the other end of the guide member, at least one hole is formed between the auxiliary guide member and the at least one of the one end and the other end of the guide member, and the fluid with the different temperature from the cooling fluid passes through the at least one hole.