A sandwich laminate, comprising: as a layer for forming a core, a sheet-form intermediate substrate obtained by impregnating a mat composed of reinforcement fibers with a thermoplastic resin; and, as layers for forming a skin, sheet-form intermediate substrates each obtained by impregnating continuous or discontinous reinforcement fiber(s) with a thermoplastic resin, wherein at least said sheet-form intermediate substrate used as said layer for forming a core has a thermal expansibility, thermal expansibility being an ability of the reinforcement fibers contained in the sheet-form intermediate substrate in a compressed state under pressure to expand due to a rising force attributed to their elastic modulus when the sheet-form intermediate substrate is heated to a temperature of not lower than the melting point of the thermoplastic resin constituting the sheet-form intermediate substrate, the usable temperature region of said thermoplastic resin constituting said layers for forming a skin and that of said thermoplastic resin constituting said layer for forming a core overlap each other over a temperature range of at least 5°C, and said thermoplastic resin has a temperature region where it does not melt at a lower limit of said usable temperature region of said thermoplastic resin; the usable temperature region of thermoplastic resin, denoted TA1 to TA2, and of thermoplastic resin, denoted TB1 to TB2, being determined as follows: as the usable lower limit temperatures TA1 and TB1, a melting point determined in accordance with JIS K7120 is used for a crystalline thermoplastic resin and a value obtained by adding 100°C to the Vicat softening temperature determined in accordance with JIS K7206 is used for an amorphous thermoplastic resin; and as the usable upper limit temperatures TA2 and TB2, values obtained by subtracting 50°C from the temperature at which a 1% weight reduction from the baseline weight is observed in each heat weight-loss curve determined in accordance with JIS K7120 are used. as a layer for forming a core, a sheet-form intermediate substrate obtained by impregnating a mat composed of reinforcement fibers with a thermoplastic resin; and, as layers for forming a skin, sheet-form intermediate substrates each obtained by impregnating continuous or discontinous reinforcement fiber(s) with a thermoplastic resin, wherein at least said sheet-form intermediate substrate used as said layer for forming a core has a thermal expansibility, thermal expansibility being an ability of the reinforcement fibers contained in the sheet-form intermediate substrate in a compressed state under pressure to expand due to a rising force attributed to their elastic modulus when the sheet-form intermediate substrate is heated to a temperature of not lower than the melting point of the thermoplastic resin constituting the sheet-form intermediate substrate, the usable temperature region of said thermoplastic resin constituting said layers for forming a skin and that of said thermoplastic resin constituting said layer for forming a core overlap each other over a temperature range of at least 5°C, and said thermoplastic resin has a temperature region where it does not melt at a lower limit of said usable temperature region of said thermoplastic resin; the usable temperature region of thermoplastic resin, denoted TA1 to TA2, and of thermoplastic resin, denoted TB1 to TB2, being determined as follows: as the usable lower limit temperatures TA1 and TB1, a melting point determined in accordance with JIS K7120 is used for a crystalline thermoplastic resin and a value obtained by adding 100°C to the Vicat softening temperature determined in accordance with JIS K7206 is used for an amorphous thermoplastic resin; and as the usable upper limit temperatures TA2 and TB2, values obtained by subtracting 50°C from the temperature at which a 1% weight reduction from the baseline weight is observed in each heat weight-loss curve determined in accordance with JIS K7120 are used. as the usable lower limit temperatures TA1 and TB1, a melting point determined in accordance with JIS K7120 is used for a crystalline thermoplastic resin and a value obtained by adding 100°C to the Vicat softening temperature determined in accordance with JIS K7206 is used for an amorphous thermoplastic resin; and as the usable upper limit temperatures TA2 and TB2, values obtained by subtracting 50°C from the temperature at which a 1% weight reduction from the baseline weight is observed in each heat weight-loss curve determined in accordance with JIS K7120 are used.