To suppress temperature variation of working fluid when quantity of heat to be received from the outside varies.

A loop type heat pipe comprises an evaporator which absorbs heat from the outside and evaporates working fluid from a liquid phase to a gas phase, condenses the working fluid at the gas phase guided from the evaporator and circulates the working fluid to the evaporator as the working fluid at the liquid phase. The evaporator comprises: a wick 130 which guides the working fluid at the liquid phase to be supplied to the inside to an outer peripheral side by capillary force, evaporates the working fluid from the liquid phase to the gas phase by the heat from the outside; a liquid reservoir part 120 which accommodates the working fluid to be supplied to the wick 130; and a capacity adjustment part 140 which adjusts capacity of the liquid reservoir part 120 according to temperature of the wick 130.