A tape cassette adapted to be detachably installed in a cassette housing portion of a tape printer that has a plurality of detecting switches (310A-310E), the tape cassette comprising: a housing including a side wall, a top wall having a top surface and a bottom wall having a bottom surface, the side wall, the top wall and the bottom wall defining a periphery of the housing, the top wall being opposite to the bottom wall in a vertical direction; and at least one tape (55, 57, 58, 59) mounted in a tape housing area (33A and 33B) defined within the periphery; wherein the housing has a box-like shape, with rounded corner portions in a plan view, that is longer in a left-and-right direction of the housing, wherein the housing further comprises a rear indentation of the bottom wall in a rear portion of the housing at a substantially center position in the left-and-right direction, wherein the rear-indentation includes a first lateral information section and a second lateral information section, each of the first lateral information section and the second lateral information section being a strip-shaped section extending along the left-and-right direction, the first lateral information section and the second lateral information section being arranged in a front-rear direction of the housing, wherein a plurality of apertures is formed in the first lateral information section and at least one aperture is formed in the second lateral information section for identifying the tape type of the tape cassette, wherein the rear-indentation further comprises a pressing portion, wherein the at least one pressing portion is a surface portion that is in the same plane as the rear indentation, and wherein, when the tape cassette is installed in the cassette housing portion, the plurality of detecting switches (310A-310E) opposes the rear indentation in the vertical direction, and each of at least one pressing portion presses a corresponding first detecting switch of the plurality of detecting switches (310A-310E). a housing including a side wall, a top wall having a top surface and a bottom wall having a bottom surface, the side wall, the top wall and the bottom wall defining a periphery of the housing, the top wall being opposite to the bottom wall in a vertical direction; and at least one tape (55, 57, 58, 59) mounted in a tape housing area (33A and 33B) defined within the periphery; wherein the housing has a box-like shape, with rounded corner portions in a plan view, that is longer in a left-and-right direction of the housing, wherein the housing further comprises a rear indentation of the bottom wall in a rear portion of the housing at a substantially center position in the left-and-right direction, wherein the rear-indentation includes a first lateral information section and a second lateral information section, each of the first lateral information section and the second lateral information section being a strip-shaped section extending along the left-and-right direction, the first lateral information section and the second lateral information section being arranged in a front-rear direction of the housing, wherein a plurality of apertures is formed in the first lateral information section and at least one aperture is formed in the second lateral information section for identifying the tape type of the tape cassette, wherein the rear-indentation further comprises a pressing portion, wherein the at least one pressing portion is a surface portion that is in the same plane as the rear indentation, and wherein, when the tape cassette is installed in the cassette housing portion, the plurality of detecting switches (310A-310E) opposes the rear indentation in the vertical direction, and each of at least one pressing portion presses a corresponding first detecting switch of the plurality of detecting switches (310A-310E).