Service life of the compressor is extended. The evaporator is provided with the housing having the suction port connectable to the suction portion of the compressor in order to evaporate at least part of a droplet or misty working fluid in the housing by a suction effect of the compressor through the suction port, comprising a filter installed in the housing, the filter dividing a space in the housing into the first space for generating the droplet or misty working fluid and the second space for communicating with the suction port, the filter being inclined away from the suction port as advancing upward, and the filter transmitting therethrough vapor resulting from evaporation of the droplet or misty working fluid while capturing the droplet or misty working fluid.