A hot-pressed member comprising: a steel chemical composition containing, by mass%, C: 0.28 % or more and less than 0.42 %, Si: 0.05 % or more and 1.5 % or less, Mn: 1.0 % or more and 3.0 % or less, P: 0.05% or less, S: 0.005 % or less, Al: 0.01 % or more and 0.50 % or less, N: 0.005 % or less, Nb: 0.001 % or more and 0.10 % or less, Ti: 0.001 % or more and 0.15 % or less, B: 0.0002 % or more and 0.0040 % or less, and optionally at least one selected from the group consisting of Mo: 0.50 % or less, Cr: 0.50 % or less, Sb: 0.001 % or more and 0.020 % or less, Ca: 0.005 % or less, Mg: 0.005 % or less, REM: 0.005 % or less, V: 0.15 % or less, Cu: 0.50 % or less, Ni: 0.50 % or less, Sn: 0.50 % or less, Zn: 0.10 % or less, Co: 0.10 % or less, Zr: 0.10 % or less, Ta: 0.10 % or less, and W: 0.10 % or less, with the balance being Fe and inevitable impurities; a microstructure in which a prior austenite average grain size is 7 μm or less, a volume fraction of martensite is 90 % or more, and at least 5 Nb-based precipitates having a grain size of 0.005 μm or more and less than 0.08 μm are present on average per 100 μm 2 of a cross section parallel to a thickness direction of the member within a range of 100 μm in the thickness direction from a surface of the member; a Ni diffusion region having a thickness of 0.5 μm or more present in a surface layer of the member; and a tensile strength of 1780 MPa or more, wherein the prior austenite average grain size, the volume fraction of martensite, the number of the Nb-based precipitates, the thickness of the Ni diffusion region and the tensile strength are measured in accordance with the specifics given in the description. a steel chemical composition containing, by mass%, C: 0.28 % or more and less than 0.42 %, Si: 0.05 % or more and 1.5 % or less, Mn: 1.0 % or more and 3.0 % or less, P: 0.05% or less, S: 0.005 % or less, Al: 0.01 % or more and 0.50 % or less, N: 0.005 % or less, Nb: 0.001 % or more and 0.10 % or less, Ti: 0.001 % or more and 0.15 % or less, B: 0.0002 % or more and 0.0040 % or less, and optionally at least one selected from the group consisting of Mo: 0.50 % or less, Cr: 0.50 % or less, Sb: 0.001 % or more and 0.020 % or less, Ca: 0.005 % or less, Mg: 0.005 % or less, REM: 0.005 % or less, V: 0.15 % or less, Cu: 0.50 % or less, Ni: 0.50 % or less, Sn: 0.50 % or less, Zn: 0.10 % or less, Co: 0.10 % or less, Zr: 0.10 % or less, Ta: 0.10 % or less, and W: 0.10 % or less, with the balance being Fe and inevitable impurities; a microstructure in which a prior austenite average grain size is 7 μm or less, a volume fraction of martensite is 90 % or more, and at least 5 Nb-based precipitates having a grain size of 0.005 μm or more and less than 0.08 μm are present on average per 100 μm 2 of a cross section parallel to a thickness direction of the member within a range of 100 μm in the thickness direction from a surface of the member; a Ni diffusion region having a thickness of 0.5 μm or more present in a surface layer of the member; and a tensile strength of 1780 MPa or more, wherein the prior austenite average grain size, the volume fraction of martensite, the number of the Nb-based precipitates, the thickness of the Ni diffusion region and the tensile strength are measured in accordance with the specifics given in the description.