A rotary compressor (4;4A) comprising: an electric motor part; a compression mechanism part (12;12A) arranged to be driven by a rotation shaft connected to the electric motor part, the compression mechanism formed to compress working fluid in operation; and a sealed case which houses the electric motor part and the compression mechanism part (12;12A), wherein: the compression mechanism part (12;12A) includes a cylinder (15;41,42), a pair of sealing members which seals both ends of the cylinder (15;41,42) to form a cylinder chamber (16;47) in the cylinder (15;41,42), a roller (21;21a) which is fitted to the rotation shaft penetrating the sealing members and is arranged so as to be able to eccentrically rotate inside the cylinder chamber (16;47), discharging ports (22,26;49a,49b,52,56) formed in the sealing members such that the working fluid compressed in a compression chamber formed in the cylinder chamber (16;47) can be discharged from the discharging ports (22,26;49a,49b,52,56), and discharging valves (23,27;50a,50b,53,57) which are configured to open and close the discharging ports (22,26;49a,49b,52,56), and one discharging port (22;49a,49b) formed in one sealing member among the pair of the sealing members is formed such that an opening area of the one discharging port (22;49a,49b) is smaller than an opening area of the other discharging port (26;52,56) formed in the other sealing member among the pair of the sealing members, characterized in that: one discharging valve (23;50a,50b), which is configured to open and close the one discharging port (22;49a,49b) having the small opening area, among the discharging valves (23,27;50a,50b,53,57) is configured to be opened by a smaller differential pressure compared to the other discharging valve (27;53,57) among the discharging valves (23,27;50a,50b,53,57). an electric motor part; a compression mechanism part (12;12A) arranged to be driven by a rotation shaft connected to the electric motor part, the compression mechanism formed to compress working fluid in operation; and a sealed case which houses the electric motor part and the compression mechanism part (12;12A), wherein: the compression mechanism part (12;12A) includes a cylinder (15;41,42), a pair of sealing members which seals both ends of the cylinder (15;41,42) to form a cylinder chamber (16;47) in the cylinder (15;41,42), a roller (21;21a) which is fitted to the rotation shaft penetrating the sealing members and is arranged so as to be able to eccentrically rotate inside the cylinder chamber (16;47), discharging ports (22,26;49a,49b,52,56) formed in the sealing members such that the working fluid compressed in a compression chamber formed in the cylinder chamber (16;47) can be discharged from the discharging ports (22,26;49a,49b,52,56), and discharging valves (23,27;50a,50b,53,57) which are configured to open and close the discharging ports (22,26;49a,49b,52,56), and one discharging port (22;49a,49b) formed in one sealing member among the pair of the sealing members is formed such that an opening area of the one discharging port (22;49a,49b) is smaller than an opening area of the other discharging port (26;52,56) formed in the other sealing member among the pair of the sealing members, the compression mechanism part (12;12A) includes a cylinder (15;41,42), a pair of sealing members which seals both ends of the cylinder (15;41,42) to form a cylinder chamber (16;47) in the cylinder (15;41,42), a roller (21;21a) which is fitted to the rotation shaft penetrating the sealing members and is arranged so as to be able to eccentrically rotate inside the cylinder chamber (16;47), discharging ports (22,26;49a,49b,52,56) formed in the sealing members such that the working fluid compressed in a compression chamber formed in the cylinder chamber (16;47) can be discharged from the discharging ports (22,26;49a,49b,52,56), and discharging valves (23,27;50a,50b,53,57) which are configured to open and close the discharging ports (22,26;49a,49b,52,56), and one discharging port (22;49a,49b) formed in one sealing member among the pair of the sealing members is formed such that an opening area of the one discharging port (22;49a,49b) is smaller than an opening area of the other discharging port (26;52,56) formed in the other sealing member among the pair of the sealing members, characterized in that: one discharging valve (23;50a,50b), which is configured to open and close the one discharging port (22;49a,49b) having the small opening area, among the discharging valves (23,27;50a,50b,53,57) is configured to be opened by a smaller differential pressure compared to the other discharging valve (27;53,57) among the discharging valves (23,27;50a,50b,53,57).