A rotary compressor, comprising: a first case (101, 201, 301) in which a stator is provided; and a second case (102, 202, 302) provided at one side of the first case (101, 201, 301) and to which a compression mechanism is coupled, and a lower cover integrated with the second case (102, 202, 302) to define an outer appearance of a lower portion of the second case (102, 202, 302), characterized in that the second case (102, 202, 302) includes: a first extension (121a, 221a, 321a) to which the compression mechanism is coupled and that extends upward from the lower cover; a step (121b, 221b, 321b) that extends to be stepped from the first extension (121a, 221a, 321a); and a second extension (121c, 221c, 321c) that extends upward from the step (121b, 221b, 321b) and is coupled to the first case (101, 201, 301), the second case (102, 202, 302) is coupled to a lower side of the first case (101, 201, 301), and a top surface of the step (121b, 221b, 321b) and a lower end (101a, 201a, 301a) of the first case (101, 201, 301) are spaced apart from each other, and the first extension (121a, 221a, 321a) is welded to the compression mechanism, and the second extension (121c, 221c, 321c) is welded to the first case (101, 201, 301). a first case (101, 201, 301) in which a stator is provided; and a second case (102, 202, 302) provided at one side of the first case (101, 201, 301) and to which a compression mechanism is coupled, and a lower cover integrated with the second case (102, 202, 302) to define an outer appearance of a lower portion of the second case (102, 202, 302), characterized in that the second case (102, 202, 302) includes: a first extension (121a, 221a, 321a) to which the compression mechanism is coupled and that extends upward from the lower cover; a step (121b, 221b, 321b) that extends to be stepped from the first extension (121a, 221a, 321a); and a second extension (121c, 221c, 321c) that extends upward from the step (121b, 221b, 321b) and is coupled to the first case (101, 201, 301), the second case (102, 202, 302) is coupled to a lower side of the first case (101, 201, 301), and a top surface of the step (121b, 221b, 321b) and a lower end (101a, 201a, 301a) of the first case (101, 201, 301) are spaced apart from each other, and the first extension (121a, 221a, 321a) is welded to the compression mechanism, and the second extension (121c, 221c, 321c) is welded to the first case (101, 201, 301). a first extension (121a, 221a, 321a) to which the compression mechanism is coupled and that extends upward from the lower cover; a step (121b, 221b, 321b) that extends to be stepped from the first extension (121a, 221a, 321a); and a second extension (121c, 221c, 321c) that extends upward from the step (121b, 221b, 321b) and is coupled to the first case (101, 201, 301), the second case (102, 202, 302) is coupled to a lower side of the first case (101, 201, 301), and a top surface of the step (121b, 221b, 321b) and a lower end (101a, 201a, 301a) of the first case (101, 201, 301) are spaced apart from each other, and the first extension (121a, 221a, 321a) is welded to the compression mechanism, and the second extension (121c, 221c, 321c) is welded to the first case (101, 201, 301).