The present invention relates to a wireless access system supporting machine type communication (MTC), and according to one embodiment of the present invention, a method by which an MTC terminal transmits a hybrid automatic repeat request-acknowledgement (HARQ-ACK) in a wireless access system supporting machine type communication (MTC) can comprise the steps of: monitoring a physical downlink control channel (PDCCH) in a monitoring section having N number of subframes; receiving at least one PDCCH in the N number of subframes; and transmitting HARQ-ACK corresponding to all subframes included in the monitoring section in the Xth subframe after the end subframe of the monitoring section.