A manual breast pump (2; 2A, 2B), comprising: a main body casing (31; 31A; 31B) having an inner space configured for the temporary collection of breast milk; a hood connected to the main body casing (31; 31A; 31B) configured to be fitted to a breast; a base part (32; 32A; 32B) which is held by the main body casing (31; 31A; 31B) and has a communicating part connected spatially to the inner space; a diaphragm configured for generating a negative pressure in the communicating part and being provided at the base part (32; 32A; 32B); a handle which is provided to be rotatable with respect to the main body casing (31; 31A; 31B) with an axis of the base part (32; 32A; 32B) as a center, and is for an operation of deforming the diaphragm, wherein the handle rotates with respect to the main body casing (31; 31A; 31B) with the axis of the base part (32; 32A; 32B) as the center; characterised in that: the manual breast pump (2; 2A; 2B) further comprises a holding member (33; 33A; 33B) which is provided at one of the main body casing (31; 31A; 31B) and the base part (32; 32A; 32B), and includes a wall part sandwiched between the main body casing (31; 31A; 31B) and the base part(32; 32A; 32B); the handle is connected to the base part (32; 32A; 32B); and when the handle rotates with respect to the main body casing (31; 31A; 31B) with the axis of the base part (32; 32A; 32B) as the center, the base part (32; 32A; 32B) rotates with the handle with respect to the main body casing (31; 31A; 31B) with the holding member (33; 33A; 33B) interposed. a main body casing (31; 31A; 31B) having an inner space configured for the temporary collection of breast milk; a hood connected to the main body casing (31; 31A; 31B) configured to be fitted to a breast; a base part (32; 32A; 32B) which is held by the main body casing (31; 31A; 31B) and has a communicating part connected spatially to the inner space; a diaphragm configured for generating a negative pressure in the communicating part and being provided at the base part (32; 32A; 32B); a handle which is provided to be rotatable with respect to the main body casing (31; 31A; 31B) with an axis of the base part (32; 32A; 32B) as a center, and is for an operation of deforming the diaphragm, wherein the handle rotates with respect to the main body casing (31; 31A; 31B) with the axis of the base part (32; 32A; 32B) as the center; characterised in that: the manual breast pump (2; 2A; 2B) further comprises a holding member (33; 33A; 33B) which is provided at one of the main body casing (31; 31A; 31B) and the base part (32; 32A; 32B), and includes a wall part sandwiched between the main body casing (31; 31A; 31B) and the base part(32; 32A; 32B); the handle is connected to the base part (32; 32A; 32B); and when the handle rotates with respect to the main body casing (31; 31A; 31B) with the axis of the base part (32; 32A; 32B) as the center, the base part (32; 32A; 32B) rotates with the handle with respect to the main body casing (31; 31A; 31B) with the holding member (33; 33A; 33B) interposed. the manual breast pump (2; 2A; 2B) further comprises a holding member (33; 33A; 33B) which is provided at one of the main body casing (31; 31A; 31B) and the base part (32; 32A; 32B), and includes a wall part sandwiched between the main body casing (31; 31A; 31B) and the base part(32; 32A; 32B); the handle is connected to the base part (32; 32A; 32B); and when the handle rotates with respect to the main body casing (31; 31A; 31B) with the axis of the base part (32; 32A; 32B) as the center, the base part (32; 32A; 32B) rotates with the handle with respect to the main body casing (31; 31A; 31B) with the holding member (33; 33A; 33B) interposed.