Abstract: Provided are a washing drying machine having a heat pump, and a drying operation control method thereof. The washing drying machine having a heat pump includes a cabinet; a tub provided in the cabinet; a drum rotatably provided in the tub; a circulation passage configured to connect a first portion of the tub to a second portion of the tub; a circulation fan provided at the circulation passage and configured to circulate air through the circulation passage and the tub; the heat pump having a compressor that compresses a refrigerant and a heat exchanger that exchanges heat with the air of the circulation passage and the refrigerant; a heater configured to heat an inside of the tub; and a controller configured to control the heater to be supplied with power in order to heat the inside of the tub before the compressor is operated during a drying course.